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Appendix A Analysis by the blowpipe

A.I The blowpipe

The blowpipe is an invaluable instrument for examining a dry . It consists essentially of a tube bent at right angles, one end having a mouthpiece and the other being terminated by a finely perforated jet. The tube should bulge out between the two extremities into a cavity, where condensed moisture from one's breath may accumulate so as not to be either carried through the jet or deposited on to the assay, which is the name given to that portion of the mineral being tested. It is important that the aperture of the nozzle of the blowpipe should be small and circular. This can be achieved by gently tapping the nozzle on an surface, inserting a square needle into the aperture and, by rotation, producing a hole of the required size and shape. The operator will probably experience some difficulty at first in keeping up a steady, continuous blast from the blowpipe, and practice will be needed to enable the instrument to be used easily. While blowing, the cheeks should be kept inflated and the air expelled by their action only, fresh air being drawn in through the nose. Trial and error are the best teachers, and practice should be continued until a steady and uninterrup• ted blast can be kept up for several minutes. A gas flame is very convenient for blowpipe experiments, but the flame of an oil or spirit lamp, or a candle, will do. If a lamp or candle is used, the wick should be bent in the direction in which the flame is blown. A portable blowpipe lamp is of particular use in the field.

A.2 The two types of flame

In blowpipe analysis it is necessary to be able to produce and to recognize two types of flames, the oxidizing flame and the reducing flame. 446 APPENDIX A: ANALYSIS BY THE BLOWPIPE

o

Figure A.I The oxidizing flame, showing the position of the blowpipe and the points of oxidation (0) and fusion (F).

The oxidizing flame An oxidizing flame is produced when the nozzle of the blowpipe is introduced into the flame so that it occupies about one-third of the breadth ofthe flame (see Fig. A.1). It is advisable to blow more strongly than in the production of the reducing flame. The oxidizing flame is and feebly illuminating, and complete combustion occurs since the air from the blowpipe is well mixed with the gases from the flame. There are two positions in this flame at which useful operations may be performed. These are the pointoffusion (position F in Fig. A.1) where the hottest part of the flame occurs, and the point of oxidation (position 0 in Fig. A.1) where the assay is heated surrounded by air, and hence oxidation takes place.

The reducing flame The reducing flame is produced when the nozzle of the blowpipe is placed some distance from the flame (Fig. A.2). The reducing flame is bright yellow and luminous, ragged and noisy. In this flame the stream of air from the blowpipe drives the whole flame rather feebly before it, and there is little mixing of air with the gases from the flame. The result is that these gases are not completely burnt, and hence will combine readily with the oxygen of any substance introduced into their midst. The assay must, therefore, be completely surrounded by the reducing flame, but not introduced too far into the flame in case a deposit of soot is formed which

Figure A.2 The reducing flame, showing the position of the blowpipe and the point ofreduction (R). SUPPORTS 447 will interfere with the heating of the assay. In Figure A.2 the point of reduction is at R.

A.3 Supports

The portion of the substance under examination (the assay) may be supported in various ways according to the requirements of each particular case. After each experiment, all supports must be thoroughly cleaned before further use. The most common supports are charcoal blocks, -tipped forceps and platinum wire. Charcoal is a good support because of its infusibility, poor heat-conduc• ting capacity, and its reducing action. The charcoal block is composed of carbon which readily combines with any oxygen which the assay may contain. Many metallic oxides may be reduced to their by heating on charcoal in the reducing flame. Sometimes, charcoal may be used as a support in oxidation, provided that its reducing action does not materially interfere with the results In order to achieve maximum success, the assay should be placed in a small hollow scraped in the charcoal block, and there should be a large area of cool charcoal beyond the hollow on which any encrustations may form. Should the assay crackle and fly about, a fresh assay must be made by powdering the substance being examined and mixing it with water into a thick paste. Points which should be noted include how easily the assay burns or flames, how easily it fuses and whether the fused assay is absorbed by the charcoal. The nature, colour, smell and distance from the assay of any encrustation are all important indicators about the nature of the elements present. Thus, for example, compounds give an encrustation far from the assay, whereas compounds give an encrustation near the assay. encrustations or residues, when moistened with nitrate and strongly reheated, give various colours characteristic of certain elements. Compounds containing or or , give char• acteristically coloured encrustations when heated on charcoal with potas• sium iodide and sulphur. Section A. 7 gives details of these and other tests. Platinum-tipped forceps are useful for holding small splinters of in the blowpipe flame. When substances are examined in this way, the colour of the flame is important, as also is the degree of fusibility of the mineral compared as far as is possible with the standard scale of fusibility, discussed in Section 2.6. A platinum wire may be used to give excellent results in nearly all the 448 APPENDIX A: ANALYSIS BY THE BLOWPIPE operations usually carried out with the forceps. When using platinum, whether as foil, wire or , care should be taken to avoid supporting minerals or other substances suspected of containing iron, lead, antimony or any other metals which can form alloys with platinum. Several elements give distinctive colours to the blowpipe flame, and this flame test is performed by introducing some of the finely powdered mineral, either by itself or moistened with HCl, into the flame on a platinum wire. The several important bead tests are carried out by fusing the mineral with a , in a small loop at the end of a platinum wire.

A.4 Fluxes

Certain substances are added to an assay so that fusion can be attained more rapidly than by heating the mineral on its own. Such substances are called fluxes, and are particularly useful when the constituents of the assay form a characteristic-coloured compound with these substances. The most important fluxes are , microcosmic salt and carbonate. Borax (Na2B40s(OHk8H20) is a hydrous sodium borate. As a blow• pipe reagent, the greater part of the attached water in the borax is first driven off by heating, and the reagent is then finely powdered. To make a borax bead, the end of a platinum wire is first formed into a loop, which is then heated to redness in the blowpipe flame and immediately dipped into the powdered borax, some of which adheres to the wire. When the loop is heated again in the blowpipe flame, the powder froths up or intumesces because of the disengagement of the water still remaining in it, and gradually fuses to a clear transparent globule, the borax head. The powdered substance to be examined is touched with the hot bead so that a small quantity sticks to it. The bead is then heated by a well sustained blast, and its colour and other characters noted, both when hot and cold, and in both the oxidizing and reducing flames. Some minerals should be added to the bead in very minute quantities, to enable the colour to be noted which otherwise might be masked. Borax changes substances to oxides, and the nature of the substance, to a large extent, can be identified by the colour and other properties of these oxides in the borax bead. Minerals containing arsenic and sulphur dissolve with difficulty in the borax bead, and their behaviour is different from oxides of the same metals. It is therefore advisable to roast the substance on charcoal in the oxidizing flame, before the test is carried out, so that any sulphur or arsenic is volatilized. Microcosmic salt (NaNH4HP04.4H20) is a hydrated ammonium hydro• gen phosphate, which is so fluid when it is first fused that it usually drops TUBE TESTS 449 from the platinum wire. Microcosmic salt should therefore either be heated on charcoal or platinum foil until the water and ammonia are expelled, and then taken up on a small platinum loop, or added to the loop in small quantities at a time until the complete microcosmic salt bead is formed. The substance under examination is added in the same way as with the borax bead test, and the whole fused in the blowpipe flame. The action of microcosmic salt is to convert the oxides of metals into complex phosphates, imparting characteristic colours to the bead both when hot and when cold; these colours often differing depending upon whether the bead is produced in the oxidizing or reducing flame. Silica is insoluble in the microcosmic salt bead, so that when silicates are dealt with, a silica skeleton appears in the bead. Sodium carbonate (Na2C03.lOH20) is used in the reduction of oxides or sulphides of metals to the metallic state. The mineral under examination is finely powdered and intimately mixed with sodium carbonate and char• coal. The mixture is moistened slightly, placed in a hollow on charcoal and heated in the blowpipe flame. The powdered mineral should amount to about one-third of the total mixture. Sodium carbonate is valuable as a flux in the analysis of silicates as it then parts with carbonic acid and is converted into sodium silicate. and give characteristic colours when introduced into the sodium carbonate bead, due to the formation of sodium manga• nate and sodium chromate. Sodium sulphide is formed from a sulphate by fusing the powdered mineral sulphate with sodium carbonate and charcoal, on charcoal. When placed on a coin and moistened, the fused mass gives a black stain of silver sulphide. Mineral sulphides give the same reaction but can be distinguished from sulphates by other tests.

A.S Tube tests

Reactions using closed and open tubes are of great importance in blowpipe analysis. The closed tube consists of narrow, soft tubing cut into 50-80 mm lengths and sealed at one end. In the closed tube, the assay is heated virtually out of contact with the oxygen of the air. In the open tube, which consists of hard glass tubing of 100-120 mm lengths and open at both ends, heating takes place in a stream of hot air and oxidation results. A small quantity of the powdered assay is introduced into the closed tube and heated. In many cases a deposit called the sublimate is formed on the cooler parts of the tube, and the colour and nature of this sublimate may 450 APPENDIX A: ANALYSIS BY THE BLOWPIPE give an indication of one or more of the elements present in the assay. Water driven out of the assay collects as droplets towards the mouth of the tube. The assay may be converted by heat into the oxides of the metals present, and some of these oxides have characteristic colours and prop• erties. Thus, for example, brown limonite (hydrated iron oxide; FeO(OH).nH20) is converted into black magnetic oxide (Fe304) by the expulsion of water, which collects on the cooler parts of the tube. With the open tube, the assay is placed towards one end and the tube inclined. The assay is thus heated in a current of air and is oxidized; characteristic smells or sublimates are formed.

A.6 Reactions

The detection of several of the acid radicles present in minerals depends on the use of reagents, such as the usual acids, powdered , granulated , etc. For instance, carbonates give off carbon dioxide (C02) on being treated with HCI, and some silicates gelatinize on being heated with the same acid. These, and other reactions, are given in the following tables.

A.7 Tables of blowpipe analyses

Flame test

The substance, either alone or moistened with HCI, HN03 or H2S04, is heated on a clean platinum wire, and colours the outer part of the blowpipe flame. brick red crimson deep crimson sodium yellow violet (masked by sodium, use blue glass filter to view flame) yellow-green emerald green with HN03 : sky blue with Hel bright green momentary yellow-green with H2S04

Indefinite blue flames are given by lead, arsenic and antimony; and indefinite green flames by , and . These elements are more satisfactorily detected by other tests. TABLES OF BLOWPIPE ANALYSES 451

Borax bead test

Element Oxidizing flame Reducing flame iron yellow hot, colourless cold bottle green copper blue opaque red chromium yellowish-green emerald green manganese reddish-violet colourless cobalt deep blue deep blue reddish-brown opaque grey yellow pale green

Microcosmic salt bead test iron colourless to brownish-red reddish copper blue opaque red chromium red when hot, green cold green manganese violet colourless cobalt blue blue nickel yellow reddish-yellow uranium yellow when hot, yellow-green hot, bright green yellow-green cold cold colourless blue-green molybdenum bright green green colourless yellow hot, violet cold silica remains undissolved in microcosmic bead chlorine saturate microcosmic salt bead with copper oxide; if a powdered chloride is added, a rich blue flame surrounds the bead

Sodium carbonate bead test

Element Oxidizing flame manganese opaque blue-green chromium opaque yellow-green 452 APPENDIX A: ANALYSIS BY THE BLOWPIPE

Reactions on charcoal

Oxidation (a) Substance heated alone in oxidizing flame on charcoal:

Element Encrustation or smell arsenic white, far from assay; smell garlic antimony white, near assay zinc yellow when hot, white when cold lead dark yellow when hot, yellow when cold bismuth dark when hot, paler when cold sulphur smell of sulphur dioxide tin yellow when hot, paler or colourless when cold molybdenum yellow when hot, yellow or colourless when cold; in reducing flame, blue

(b) White encrustations and residues, obtained from (a) above, moistened with cobalt nitrate and strongly reheated:

Element, etc. Colour zinc encrustation grass green tin encrustation blue-green antimony encrustation dirty green magnesium residue pink residue blue and unfused fusible silicates, phosphates residue blue fused and glassy-looking and borates

( c) Substance heated in oxidizing flame with potassium iodide and sulphur:

Element Encrustation lead brilliant yellow bismuth scarlet; yellow near assay mercury greenish-yellow; and greenish-yellow fumes TABLES OF BLOWPIPE ANALYSES 453 Reduction (a) Substance mixed with powdered charcoal and sodium carbonate and heated in oxidizing flame:

Element Bead or residue obtained lead soft malleable metallic bead; easily fused; marks paper tin tin white bead, soft and malleable; not marking paper silver silver white malleable bead yellow bead, soft and malleable bismuth silver white bead, brittle copper red spongy mass iron residue strongly magnetic cobalt residue feebly magnetic nickel residue feebly magnetic

(b) Special reduction tests for titanium and tungsten. Substance fused with powdered charcoal and sodium carbonate; the residue boiled with hydro• chloric acid and few grains of granulated tin:

Metal Colour of solution titanium violet tungsten Prussian blue

Substance fused with powdered charcoal and sodium carbonate; the residue dissolved in concentrated sulphuric acid with an equal volume of water added; the solution is cooled, water added, and then hydrogen peroxide added:

Metal Colour of solution titanium amber 454 APPENDIX A: ANALYSIS BY THE BLOWPIPE

Closed tube test Assay heated in closed tube, either alone, or with sodium carbonate and powdered charcoal, or with magnesium:

Element, etc. Observation sulphur orange sublimate arsenic black sublimate; smell of garlic mercury, with sulphur black sublimate, red on rubbing arsenic, with sulphur reddish-yellow sublimate, deep red while liquid antimony, with sulphur brownish-red sublimate, black while hot water colourless drops mercury heat with sodium carbonate and charcoal, globules of mercury as sublimate arsenic heat with sodium carbonate and charcoal; black mirror of arsenic, soluble in sodium hypochlorite phosphates heat with magnesium and add water; characteristic smell of phosphoretted hydrogen

Open tube test Assay heated in open tube:

Element Observation sulphur sulphurous fumes of sulphur dioxide arsenic white sublimate, crystalline, volatile, far from assay; smell of garlic antimony white sublimate near assay whitish sublimate, fusible to colourless drops TABLES OF BLOWPIPE ANALYSES 455

Reactions for acid radicle

Acid radicle Test carbonate With hydrochloric acid, carbon dioxide evolved, turning lime-water milky sulphides (some) With hydrochloric acid, sulphuretted hydrogen evolved. Also indicated by closed tube, open tube and charcoal tests, g. v. fluoride With strong sulphuric acid, greasy bubbles of hydrofluoric acid cvolved, causing deposition of a white film on silica on a drop of water held at the mouth of the tube chloride With sulphuric acid and manganese dioxide, greenish chlorine evolved. Also detected by microcosmic salt bead saturated with copper oxide, g.v. bromide With sulphuric acid and manganese dioxide, brown bromine evolved iodide With sulphuric acid and manganese dioxide, violet iodine evolved nitrate With sulphuric acid, brown nitrous fumes evolved silicates (some) With hydrochloric acid, gelatinize. Silica skeleton in microcosmic salt bead sulphate Heat substance on charcoal with sodium carbonate and powdered charcoal; place residue on silver coin and moisten. Black stain indicates sulphate (or sulphide) phosphate Heat with magnesium in closed tube, add water; phosphoretted hydrogen evolved. Also detected by giving a fused blue mass when heated on charcoal, moistened with cobalt nitrate and strongly reheated telluride Heat powdered mineral with a little strong sulphuric acid; reddish-violet solution; colour disappears on adding water to the cold solution and a grey precipitate is deposited 456 APPENDIX A: ANALYSIS BY THE BLOWPIPE

Summary of tests for metals aluminium Heated on charcoal, moistened with cobalt nitrate, strongly reheated, blue unfused residue antimony Roasted on charcoal, white encrustation near assay. Heated in open tube, white sublimate near assay. Heated in closed tube, red-brown sublimate; black when hot arsenic Roasted on charcoal, white encrustation far from assay; garlic smell. Heated in open tube, white volatile sublimate. Heated in closed tube with sodium carbonate, black arsenic mirror, soluble in sodium hypochlorite barium Flame test, yellow-green bismuth Reduction on charcoal, brittle bead. Roasted with potassium iodide and sulphur, yellow encrustation near assay; outer parts scarlet calcium Flame test, brick red Heated on charcoal with sodium carbonate, reddish-brown sublimate chromium Borax bead, green; microcosmic salt bead, green; sodium carbonate bead, yellow-green, opaque cobalt Borax bead, deep blue; microcosmic salt bead, deep blue copper Flame test, emerald green with nitric acid, sky blue with hydrochloric acid. Borax bead, blue in oxidizing flame; opaque red in reducing flame. Reduction on charcoal, red metallic copper gold Reduction on charcoal, soft malleable gold bead iron Borax bead, yellow hot, colourless cold, in oxidizing flame; bottle green in reducing flame. Reduction on charcoal, magnetic residue lead Reduction on charcoal, malleable metallic bead, marking paper. Roasted with potassium iodide and sulphur, brilliant yellow encrustation lithium Flame test, deep crimson; deeper than strontium flame magnesium Heated on charcoal, moistened with cobalt nitrate, strongly reheated, pink residue manganese Borax bead, reddish-violet in oxidizing flame; colourless in reducing flame. Microcosmic bead, violet in oxidizing flame; colourless in reducing flame. Sodium carbonate bead, blue-green opaque mercury Heated on charcoal with potassium iodide and sulphur, greenish-yellow encrustation and greenish-yellow fumes. Heated in closed tube with sodium carbonate and charcoal, globules of mercury as sublimate TABLES OF BLOWPIPE ANALYSES 457 molybdenum Microcosmic salt bead, bright green in oxidizing flame; dirty green hot, fine rich green cold, in reducing flame. Roasted on charcoal, yellow hot, yellow or colourless cold; in reducing flame, blue nickel Borax bead, reddish-brown in oxidizing flame; opaque grey in reducing flame potassium Flame test, violet, view through blue glass filter silver Reduction on charcoal, silver bead sodium Flame test, yellow strontium Flame test, crimson tellurium Heated in open tube, whitish sublimate, fusible to colourless drops. Heated with strong sulphuric acid, reddish-violet solution thallium Flame test, bright green tin Reduction on charcoal, tin bead titanium Microcosmic salt bead, yellow hot, violet cold, in reducing flame. Reduction with tin, violet solution. Hydrogen peroxide test, amber solution tungsten Microcosmic salt bead, blue-green in reducing flame. Reduction with tin, blue solution uranium Microcosmic salt bead, yellow hot, yellow-green cold, in oxidizing flame; yellow-green hot, bright green cold, in reducing flame zinc Roasted on charcoal, encrustation yellow when hot; white when cold. Heated on charcoal, moistened with cobalt nitrate, and strongly reheated, grass green encrustation Appendix B Hydrocarbons

B.1 Introduction Many substances are included in this appendix, differing from each other in mode of occurrence, physical properties and chemical composition, but with each consisting mainly of carbon, and also containing oxygen and hydrogen. The substances are considered in two groups: coals and bitumens.

B.2 Coals The name 'coal' is applied to a number of different substances largely made up of carbon, hydrogen and oxygen, all of which more or less represent the altered remains of land vegetation transformed by slow chemical changes (principally the elimination of oxygen and hydrogen from the original woody tissue), into a material containing a higher percentage of carbon. Two hypotheses can explain the origin of coal: (1) growth in place considers coal to result from the decay of vegetable matter in situ, and this explains the origin of pure well-bedded extensive coals, such as bituminous coal; while (2) drift has been advanced to explain the formation of impure current-bedded coals, such as some types of cannel coal, which are thought to be the result of drifted vegetable manner becoming buried in a delta or estuary. According to the geological history it has undergone, coal contains varying amounts of carbon, oxygen, hydrogen and nitrogen, with the least altered varieties such as lignite containing large amounts of the gaseous elements, and the most altered varieties such as anthracite containing as much as 95% carbon. Several varieties of coal can be distinguished, and typical chemical analyses of the main varieties are given in Table B.lo Whatever the origin of coal is, its final character has been largely influenced by the processes of organic decay. Coal-bearing seams may be of differing geological ages. Most coals are of Carboniferous age, and the coal-bearing strata of the UK, Pennsylvania, West Germany, India, etc. are of this age. In Britain, the Carboniferous rocks have been gently folded and, although the coal-bearing beds have been removed from the crest of the folds by subsequent erosion, they have been preserved in the troughs or coal basins. Examples of such basins are COALS 459

Table B.l Composition of types of coals (expressed as percentages).

C 0 H N wood 49.65 43.20 6.23 0.92 peat 55.44 35.56 6.28 1.72 lignite 72.95 20.50 5.24 1.31 bituminous coal 84.24 8.69 5.55 1.52 anthracite 93.50 2.72 2.81 0.97 afforded by the Lancashire coalfield and the Yorkshire coalfield, which occupy downfolded troughs on either side of the Pennines. Other extensive coals also occur, however, which are of different geological ages from the Carboniferous, although these deposits are usually less valuable both in quality and thickness. A small Jurassic coal seam was recently worked at Brora in the far north of Scotland, and Cretaceous coals occur in the USA and Europe. In some countries Tertiary coals have also been worked. Coals are classified or ranked in various ways, including:

(a) The fuel ratio, which is the ratio of fixed carbon to volatiles. (2) The calorific value, which is the amount of heat produced by the burning of a standard unit of coal. This used to be measured in British thermal units, but now is measured in joules (1 Btu = 1055.16 joules. (3) Carbon content, content of volatiles and water content. (4) The nature of coke produced by the coal.

From the above, Table B.2 can be compiled, and is shown overleaf. The main varieties of coal are described below.

PEAT Peat results from the accumulation of vegetable matter such as mosses and other bog plant, and forms extensive deposits in Eire, the USSR, the USA and elsewhere. Its organic nature is evident throughout the entire deposit, although the bottom layers may become compressed through time into a compact, homogenous substance with an increased carbon content.

LIGNITE, BROWN COAL Lignite marks a further stage in the alteration of the vegetable matter which, although compact and possessing a brilliant lustre, still contains impressions and remains of fragments of vegetation, leaves, etc. Lignites 460 APPENDIX B: HYDROCARBONS Table B.2 Coal classification based on calorific value, carbon content, water content and percentage of volatiles present.

Coal type Calorific Carbon Water Volatiles value (MJ)· (%) (%) (%) lignite 7.4-11.6 45-65 >20 lignitic or semi-bituminous 10.5-13.7 60.75 6--20 cannel 12.7-16.9 30-40 low-carbon bituminous 12.7-14.8 70-80 <6 <35 bituminous 14.8-16.9 75-90 12-26 anthracitic and high-carbon bituminous 16.0-16.9 80-90 12-15 semi-anthracite 15.8-16.4 90-93 7-12 anthracite 15.3-15.9 93-95 3- 5

• MJ = megajoules; i.e. 106 joules. contain a large amount of water (more than 20%, Table B.2), and may change to powder on drying. Lignite beds are found at several horizons in more recent geological formations, as in East Germany (see Chapter 7 under Carbon; East Germany produces 300 Mt per year of lignite or soft coal), the USSR, West Germany, Czechoslovakia and Yugoslavia. The name brown coal is often restricted to a coal in which the evidence of vegetable matter is not so obvious as in lignite. Jet is a resinous, hard, black variety of lignite, capable of taking a high polish, and therefore suitable for ornaments. It is found at Whitby in Yorkshire and elsewhere.

CANNEL COAL Cannel is a variety of coal which ignites in a candle flame, and burns with a smoky flame. It is one of the bituminous coals, but differs from the usual types in its composition, lustre, and colour. It is dense, has no lustre, has a conchoidal fracture, is dull grey or black and contains a large amount of gas. Microscopic examination reveals that cannel is typically composed of spore and pollen remains, with an abundance of those of oil-bearing algae. On distillation, cannel produces a large amount of volatiles (30-40%), and is valuable for the amount of different oils it produces. Torbanite, or boghead coal, is a variety of cannel arising from the deposition of vegetable matter in lakes. It is found at Torban and Boghead, and other localities in the Central Valley of Scotland, and forms lenticular deposits in New South Wales. Its exploitation in Scotland gave rise to a celebrated lawsuit which involved an accurate description of the term 'coal'. BITUMENS 461 BITUMINOUS COALS SG 1.14--1.40 Bituminous coals vary considerably in character, but they all burn with a smoky flame, and during combustion soften and swell in a manner resembling the fusion of pitch or bitumen. This, however, is merely the first stage in the process oftheir destructive distillation, and there is no bitumen present. They all have a bright, pitchy lustre, and different varieties are distinguished by their manner of burning such as, for example, coking and non-coking coal. Most household coal is bituminous coal, which usually shows banding parallel to its bedding. The bedding planes are marked by a soft, powdery, charcoal-like material called fusain; other bands parallel to the fusain layers include durain, which is hard and dull, c1arain, which has a brighter lustre, and vitrain, which occurs as bright, glassy-looking streaks. All these layers should be identified in the hand specimen.

ANTHRACITE SG 1.0-1.8 HD 0.5-2.5 Anthracite is black or brownish black in colour, and sometimes iridescent. It has a black and does not soil the fingers. It has a brilliant lustre and breaks with a conchoidal or uneven fracture. It is less easily set alight than other coals, and burns with little flame and virtually no smoke, which explains its importance as a fuel in 'smokeless zones', and during its combustion it gives out much heat. Passages from ordinary coal into anthracite have been recorded, and anthracite usually occurs where coal-bearing strata have been subjected to increased temper• tures and pressures. There are exceptions, and some anthracites may be formed by the alteration of the vegetable matter before its entombment. Anthracite occurs in the coalfields of South Wales, Scotland and Pennsylvania.

B.3 Bitumens

Bitumens are essentially hydrocarbons belonging to both the paraffin series, CnH2n+2, and the napthalene series, CnH 2n• Different proportions of these give different bitumens, although each bitumen may contain smaller amounts of allied hydrocarbon series. The bitumens include liquid, light yellow oils, with an SG of 0.771, solid asphalts, and waxy materials such as ozokerite. The various bitumens are now described. 462 APPENDIX B: HYDROCARBONS

Table B.3 The geological ages of some of the world's oilfields.

Age OilfieIds

Tertiary Middle East (Saudi Arabia, Iraq, Iran, Gulf States, etc.) California, Rumania, Venezuela, Mexico, Burma, southern USSR oilfieIds

Mesozoic North Sea, Texas, Wyoming, Galicia Upper Palaeozoic Texas, Oklahoma, Kansas, Pennsylvania, Illinois, Canada Lower Palaeozoic Indiana

CRUDE PETROLEUM, NAPTHA, MINERAL OIL Petroleums include brownish or blackish liquids, often with a greenish tinge, generally lighter than water, and with a powerful smell. Fractional distillation produces various economic oils such as petroleum spirit, benzene, etc. The light products are used in the internal combustion engine, the intermediate products for lighting, and the heavy products for lubri• cation and fuel oils. Crude oil is the basis of the petrochemical industry. Crude oil is a mineral of organic origin found in host rocks (sandstones, etc.) which have been folded or faulted so that the oil has accumulated, and then been trapped within the host rock by overlying impervious rock layers, which prevent the oil migrating. The presence of crude oil may be shown by either oil seepage at the surface, or the presence of bitumen or pitch deposits caused by the evaporation and oxidation of volatile hydro• carbons. Table B.3 gives the ages of the main oilfields of the world.

ASPHALT, asphaltum, mineral pitch Asphalt is a mixture of different hydrocarbons, black or brownish in colour, usually soft, but sometimes hard with a conchoidal fracture. In suitable solvents such as carbon bisulphide, asphalt may be dissolved either into various hydrocarbons, or into a non-bituminous organic substance containing any inorganic matter present in the crude material. Asphalt formed from the oxidation of crude oil occurs in quantity in the famous pitch lakes of Trinidad, and also in Alberta, Canada, Venezuela and Cuba. Asphalt has been found in various localities in England, as at Castleton (Derbyshire), Pitchford near Shrewsbury, and Stanton Harold in Leicestershire where it is found encrusting crystals of galena and chalcopyrite; but all these occurrences have no commercial value what• soever. In some occurrences porous sedimentary rocks such as sandstones become impregnated with the asphalt, and from these the asphalt can be extracted. BITUMENS 463 Asphalt is a particularly important material since most road surfaces are composed of aggregate, which may be either crushed rock or sand and gravel of a particular grading, mixed with hot asphalt or bitumen (as it is known commercially), and this coated material is then spread over the bottom layers of a road, with a top layer, called the wearing course, finally being laid down.

ELATERITE, elastic bitumen, mineral caoutchouc Elaterite is a soft, elastic, solid bitumen, not unlike rubber in its physical properties. It has been reported from Castleton (Derbyshire), Neufchatel and elsewhere.

ALBERTITE, gilsonite, grahamite, uintaite, wurzillite All of these substances are varieties of solid bitumen which differ slightly in their physical and chemical properties. They usually occur infilling fissures, as in New Brunswick, and have been derived from oil-bearing rocks.

OZOKERITE Ozokerite resembles beeswax in appearance. It is dark yellow or brownish in colour, often with a greenish opalescence. It is found associated with crude oil in Utah, Moldavia and Galicia, where it was mined. In Galicia, ozokerite has been squeezed into fractures, where it forms vein-like bodies. Material oozing upwards from depth refills these fractures as the ozokerite is removed. When purified it forms ceresine, which is used in the manufacture of candles.

HATCHETTINE This is a colourless or yellowish, soft, waxy substance, resembling ozoker• ite. It has been found in cracks in ironstone nodules at Merthyr Tydfil in Wales.

AMBER SG 1.1 HD 2.0-2.5 RI 1.54 Amber is a fossil resin much used for beads and pendants, and in ornaments, although this latter use is found only in objects of great antiquity. Amber varies in colour from deep orange-yellow to pale yellow, and to sometimes white. It is often cloudy, and contains leaves, fossil insects, etc. When heated, amber leaves a black residue which is used in the manufacture of the best varnishes. Amber occurs as irregular nodules in recent sediments, deposited under estuarine (shallow-water) conditions, and is worked commercially on the southern coast of the Baltic. 464 APPENDIX B: HYDROCARBONS COPALITE, Highgate resin Copalite is a pale yellow or brownish, waxy substance, found in small films or fragments in the London Clay, at Highgate Hill, London. It burns easily with a smoky flame, and leaves little ash.

GUMCOPAL Gum copal is resin found buried in modern sands, as in New Zealand. It is of inferior quality to amber. Bibliography

Ahrens, L. H. 1952. The use of ionisation potentials, Part 1. Geochimica et Cosmochimica Acta 2, 155-69. Best, M. G. 1982. Igneous and metamorphic geology. New York: W. H. Freeman. Bravais, A. 1848. In Ostwald's Klassiker der exakten Wissenschaften 90 (1897). Bloss, F. D. 1971. Crystallography and crystal . New York: Holt, Rinehart & Winston. Deer, W. A., R. A. Howie & J. Zussman 1966. An introduction to the rock-forming minerals. London: Longman. Deer, W. A., R. A. Howie & J. Zussman 1978 et seq. Rock-forming minerals (various volumes). London: Longman. Dixon, C. J. 1979. Atlas of economic mineral deposits. London: Chapman & Hall. Evans, A. M. 1987. An introduction to ore geology, 2nd edn. Oxford: Blackwell. Gillen, C. 1982. Metamorphic geology. London: Allen & Unwin. Goldschmidt, V. M. 1937. The principles of distribution of chemical elements in minerals and rocks. Journal of the Chemical Society of London 1937, 655-73. Henderson, P. 1982. Inorganic chemistry. Oxford: Pergamon Press. Lindgren, W. 1933. Mineral deposits, 2nd edn. New York: McGraw-HilI. Mason, B. 1966. Principles of geochemistry, 3rd edn. New York: John Wiley. Mining Journal 1980 et seq. Mining annual review. Miyashiro, A. 1973. Metamorphism and metamorphic belts. London: Allen & Unwin. Palache, C., H. Berman & C. Frondel 1944. Dana's system of mineralogy. New York: John Wiley. Pauling, L. 1960. The nature of the chemical bond, 3rd edn. Ithaca, New York: Cornell University Press. Phillips, F. C. 1963. An introduction to crystallography, 3rd edn. London: Longman. Phillips, W. R. & D. T. Griffin 1981. Optical mineralogy: the non-opaque minerals. New York: W. H. Freeman. Ringwood, A. E. 1955. Principles governing trace element distribution during magmatic crystallization, I. The influence of electronegativity. Geochimica et Cosmochimica Acta 7, 189-202. Stanton, R. L. 1972. Ore petrology. New York: McGraw-Hili. Vernon, R. H. 1976. Metamorphic processes. London: Allen & Unwin. Index

Abbe refractometer 86 alstonite 304 accessory plates 89, 97 alteration (of mineral) 112 acicular 32 alum 323 acid salt 21 aluminite 331 acid(ic) magma 121 aluminium minerals 143, 170--2 acids 20, 21 aluminosilicates 120 acmite 381 alumstone 329 actinolite 390, 396 alunite 329-30 acute bisectrix (Bxa) 100, 105 alunogen 329 adamantine 29 amadou 361 addition 96 amazonstone 418 adularia 421 amber 463 aegirine 381-2 amesite 406 aegirine augite 381-2 amethyst 428 aegirite 381 ammonium salts 184-5 aenigmatite 395 amorphous 32 agaric mineral 289 amosite 389, 396 agate 427, 430 amphibole group 386-7 agglomerate 125 amphibolized 390 aggregate polarization 112 amygdaloidal 32, 123 airborne magnetometer 44 analcime 437, 438, 439 iikermanite 368 analyser 89, 116 AhSiOs polymorphs 357-8 anatase 271-2 AhSiOs production 358 andalusite 357, 358-9 alabandite 236-7 andesine 417 alabaster 324 andradite 354, 355, 356 albertite 463 anglesite 319-20 albite 417 angstrom 52 albite law 418 anhedral (mineral) 111, 418 alexandrite 285 anhydrite 320--1 Algerian onyx 289 anhydrous salt 22 alkali amphiboles 386, 391-7 anions 8 alkali feldspars 417, 420--2 anisotropic crystals 91 alkaline 20, 30 ankerite 302 alkaline magma 124 annabergite 335, 336 allanite 367 annite 401, 402 alliaceous 30 anomalous interference colours allochthonous deposits 141, 142 96 aUophane 410, 415 anorthite 417 almandine 354, 355-6 anthophyllite 387-8 INDEX 467 anthracite 45R, 459, 461 Atterberg limits 410 anthraconite 290 augite 379-80 antigorite 407 autochthonous deposits 141, 142-3 antimonial nickel 241-2 autunite 343 antimonite 246 aventurine feldspar 421 antimony glance 246 aventurine quartz 428 antimony minerals 1RR--90 axes of reference 55 antiperthites 419 axinite 373--4 apatite 33&-9 axis of symmetry 57 aperture diaphragm 90 azurite 309-10 aphrite 2R9 apophyllite 410, 415-16 back-arc basins 127 aquamarine 370 balas-ru by 282 aragonite 291, 29&--R Banket 213 arborescent 33 barite 317-18 arc-trench greywackes 133 barium feldspar 426--7 arenaceous rocks 130 barium minerals 161-2 arendalite 366 barytes 317-18 arenites 129, 130 barytocalcite 304 arfvedsonite 394--5 basabisutite 309 argentiferous grey copper ore 255 basal 35 argentine 2R9 basaltic hornblende 393 argentite 232 base metal deposits 141 argillaceous 31 bases 20 argillaceous rocks 130 basic magma 121 argillic zone 139 basic salt 21-2 aristotypes 34 basobisutite 309 arkoses 129, 130 bastite 377, 408 arquerite 216 batholiths 125 arsenic minerals 1R&--R bauxite 277-8 arsenical nickel 241 Baveno law 418 arsenical pyrites 249-50 Becke line 86--7, 89 arsenious acid 265 beidellite 410, 413 arsenolite 265 bell metal ore 239 arsenopyrite 206, 249-50 bentonite 412-13 asbestos 395-7 Berlin blue 96 asbestosis 397 Berlin brown 96 asbolan 269 Berman torsion balance 43 asbolite 269-70 Bertrand lens 90, 116 asparagus stone 33R beryl 370--1 asphalt 462-3 minerals 162-3 assay 445 Besshi type deposits 140 asthenosphere 126, 133 biaxial indicatrix 91, 99-107 astringent 30 biotite 401-2 atacamite 229 birefringence 94, 112, 113 atom 3 bismite 273 atomic bonding 9 bismuth glance 246--7 atomic number 6 bismuth minerals 190--1 atomic weight 4--5, R, 9 bismuth ochre 273 attapulgite 414 bismuthinite 246--7 46R INDEX bismutite 309 breithauptite 241-2 bitter 30 brimstone 221 bitter spar 302 brittle 3R bitterns 225 brittle micas 403 bitumens 461-4 brittle silver ore 253-4 bituminous coal 459, 461 broccanthite 326 black jack 237-R broggerite 273 black lead 223 bromides 203 black oxide of cobalt 269 bromlite 304 black tellurium 232 bromoform 42 blackband 293 bromyrite 203, 228 bladed 32 bronzite 377 blende 237-R brookite 272 bloodstone 430 brown coal 459-60 blowpipe 445 brown hematite 280 blowpipe analysis 25, 445-5R brown spar 302 blowpipe tests 450--7 brucite 274--5 blue asbestos 392 buchites 360 blue carbonate of copper 309 bustamite 385 blue john 22R bytownite 417 blue lead 235 blue vitriol 325 cadmium minerals 167 blue-iron earth 335 Cairngorm 428 blueschist metamorphic belts 132 calamine 369 blueschists 367-R, 3R2, 390, 392-3 calamine (UK) 295 body-centred cubic packing 11, 13 calaverite 251 boehmite 27R calc spar 288 bog iron ore 2RO calc tufa 289 Bl'lggild intergrowths 419 calc-alkaline igneous rocks 124 boghead coal 460 calc-alkaline plutonic rocks 127 Bologna stone 317 calc-alkaline volcanic rocks 127 boracite 315-16 calcareous tufa 289 ~-boracite 315-16 calcilutites 130 borax 312-13 calcite 288-91 borax bead 44R calcium minerals 159-60 bornite 234--5 calculation of mineral formula 24--5 boron minerals 169-70 calomel 228 boronatrocalcite 314 calorific value (of coals) 460 bort 222 cancrinite 432, 435, 436 bortz 222 cannel coal 458, 460 bosses 125 capillary pyrites 242 botryoidal 33 Ca-poor amphiboles 386, 387 boulder 317 carbon content (of coals) 460 bournonite 256--7 carbon minerals 176-8 Bragg equation 50,117 carbonate of lime 288, 290 braunite 266 carbonatites 127, 137 Bravais lattice 55 carbuncle 356 Brazil law 427 Ca-rich amphiboles 386, 389 Brazilian emerald 373 Carlsbad-albite twins 423, 425 Brazilian sapphire 373 Carlsbad law 418 INDEX 469 carnallite 230 chromium minerals 191-2 carnelian 430 chrysoberyl285-6 carnotite 343-4 chrysolite 350 Cassin ian curves 102 chrysotile 396, 407, 409 cassiterite 270 cinnabar 243-4 cations 7 cinnamon-stone 355 eat's eye 392, 428 circular sections 100 caulk 317 citrine 428 celadonite 400 clarain 461 celestine (celestite) 318-19 classification of igneous rocks 124-5 celsian 426 classification of rocks 118 centre of symmetry 57 clastic rocks 129 cerargyrite 227-8 clay ironstone 293 ceresine 463 clay minerals 410 minerals 175-6 clay production 411-12 ceruse 300 clayey 31 cerussite 300-1 cleavage 35-{), 111 cervantite 273 cleavage plane 35 ceylonite 281 cleavelandite 421 chabazite 438, 443 Clerici's solution 42 chain silicates 120, 374-97 cleveite 273 chalcanthite 325-6 clinochlore 406 chalcedony 427, 430 clinographic projection 77, 79 chalcocite 234 clinozoisite 364-5 chalcopyrite 238-9 clintonite 404 chalcotrichite 258-9 coal classification 460 chalk 290 coal production 177 chalybite 293 coal rank, 459 chamosite 406 coals 458-61 change of colour 27 cobalt bloom 335-6 charge 8 cobalt minerals 207 chemical analysis 23-5 cobaltite 249 chemical balance 40-1 coccolite 379 chemical composition of igneous rocks cockscomb barytes 317 119 coesite 427 chemical sedimentary rocks 130 coke 459 chert 431 colemanite 314-16 chessylite 309 collophane 338 chiastolite 358 colophonite 355 Chile saltpetre 310 colour 26-8,111,116 china clay 410, 411 columbite 287-8 chloanthite 252-3 columnar 33 chlorapatite 336 commercial asbestos 396 chlorides 202 common garnet 355 chlorite 407 common hornblendes 390-1 chlorite group 406 common mica 398 chloritoid 363 common orthoclase 421 chrome diopside 379 common salt 224 chromite 284 compensation 96 chromite series 284 compounds 1, 2 470 INDEX compylite 340 crystal 47, 65-8 conchoidal 36 crystal chemical classification of silicate concretionary 33 minerals 148, 348-50 condenser lens 90, 9R crystal chemistry 48 contact goniometer 61 crystal classes 59 contact metamorphism 131 crystal drawing 77-9 continental alkaline rocks 127 crystal form 31 continental deposits 12R crystal lattice 15 continental tholeiitic rocks 127 ( s) 57, 59, 68-77 continental crust 126 crystalline 31 convergent lens 90 crystalline silica 427 cooling 30 crystallization 45 coordination 53 crystallized 31 coordination number 16, 17 crystallographic axes 55, 65-6, 67, 68 coordination state 15 crystallography 26,31,47 copalite 464 crystobalite 427, 429-30 copper glance 234 cubic 55,69-70 copper minerals 153-6 cubic close-packing 11, 12-13 copper nickel 241 cubic form 59 copper pyrites 23&-9 cummingtonite 388-9 copper uranite 342 cuprite 258-9 copper vitriol 325 Curie point 45 copperas 326 cyanite 359 coprolite 337 cyanosite 325 cordierite 371-2 cyclosilicates 120, 370-4 core 2 Cyprus type deposits 140 corundum 261-3 cossyrite 395 d-spacing 117 covalent bonding 9,10-11 damourite 398 covellite (covelline) 243 Dana classification scheme 147 critical angle R5 dark red silver ore 254-5 crocidolite 392, 396 daughter product 46 crocoise 332 Dauphine law 427 crocoisite 332 Debye-Scherrer camera 51 crocoite 332 degree of roundness 128 cromfordite 30R degree of sorting 129 cronstedtite 406 degrees of intensity 29 cross wires R9 demantoid 355 cross-bedding 129 dendritic 33 crossed polars (XP) 90 density 39 crossi te 392 depth-temperature classification cross-stone 442 scheme (or ores) 134-6 crude oil 462 Derbyshire spar 228 crude petroleum 462 desert-roses 325 crust 2, 126 desmine 443 cryolite 230-1 detrital rocks 129 cryptocrystalline 32 diagenesis 128 cryptocrystalline silica 427 diallage 378, 380 cryptoperthites 419 dialogite 294-5 crysoprase 430 diamond 222 INDEX 471

diamond production 177 eluvial placers 213 diaspore 27'1\ embolite 203, 228 diatomaceous earth 431-2 emerald 370 diatomite 427, 431-2 emerald nickel 209, 306 diatreme 12'1\ emery 262 dichroiscope 109 enargite 256 dichroite 371 enargite group 256 dickite 410 endellionite 256--7 differentiation 126 enstatite 376--7 diffusion column 40, 43 environmental-rock association scheme digenite 234 (for ores) 136 dimorphous crystals 34 epidote 365-6 diopside 37R--9 epidote group 363--4 diopside solid solution series (di,,) 378 epithermal deposits 135-6 dispersion 84 cpsom salts 327 disthene 359 epsomite 327 divergent 33 erubescite 234 dog-tooth spar 289 erythrite 335-6 dolomite 130, 302, 303 euhedral (mineral) 111 dolomite-ankerite series 302-3 eulysites 389 dolomites 178 evaporites 130 double-chain silicates 120, 386--97 exsolution lamellae 377-8 dravite 372, 373 external form (of crystal) 47 dull lustre 28, 29 extinction angle 106, 114-15 durain 461 extinction position 94 dyke swarms 125-6 extraordinary (E) rays 92 dykes 125 extrusive igneous rocks 123 dynamic metamorphism 131 eyepiece 89

Earth history 144-6 fabric of metamorphic rocks 131 earthy cobalt 269 fahlerz 255 eckermannite 394-5 famatinite 256 eclogites 382 fayalite 350, 351 edenite 390 feel 26, 31 Egyptian jasper 431 feldspar group 416--27 elastic 38 feldspathoid family 432 elastic bitumen 463 fenite 128 elaterite 463 ferberite 344 elbaite 372, 373 ferrimolybdite 346--7 electric calamine 369 ferroactinolite 389 electrochemical series 22-3 ferroaugite 379-80 electromagnetic separation 44 ferromagnesian silicates 120 electrons 3 ferruginous quartz 428 element groups 19 fibrolite 359 element periods 19 fibrous 32 elements 1 field diaphragm 90 elements of symmetry 57, 58, 59 filiform 33 eleolite 433 first-order red plate 97 ellsworthite 286 first -order spectrum 95 Elmore process 39 flame test 448 472 INDEX flexible 38 geyserite 431 flint 427, 430, 431 gibbsite 277 float stone 431 gilbertite 398 flos- ferri 297 gilsonite 463 flotation process 39 glassy 123 fluids 1 glauber salt 322 fluorapatite 336 glauberite 321-2 fluorescence 26, 30 glauconite 400 fluorides 202, 203 glaucophane 391-3 fluorite 228--9 glide-planes 36 fluorspar 228--9 gliding 13 fluxes 448--9 goethite 279 focusing (of microscope) 89 gold amalgam 214 foliaceous 32 gold minerals 157-9 foliated 32 Goldschmidt's rules 15 Fontainebleau sandstone 290 goniometer 51, 61-2 form 31, 59, 60,111 goslarite 327-8 formula 3 gossan 144,228 formula-weight 8 graded bedding 129 forsterite 350, 351 grahamite 463 foetid 31 granular 33 fowlerite 385 granulites 131 fractionation 126 graph recorder 51-2 fracture 36 graphic intergrowth 422 framework silicates 120, 416--44 graphic tellurium 251-2 franklinite 282, 283, 353 graphite 223 freibergite 255 greasy 31 freieslebenite 257 great circle 63 French chalk 405 green vitriol 326 fuel ratio (of coals) 459 greenalite 406 Fuller's earth 415 greenlead ore 339, 340 fusain 461 greenockite 167, 239-40 fusibility (of a mineral) 43-4 greenovite 354 greenschists 132, 390, 407 gahnite 281 greisen 361 galaxite 281 grey antimony 246 galena 235-6 grossular 354, 356 gallium 172 grunerite 388-9 galmei 369 gum copal 464 gangue 134 gypsite 324 garnet group 354-6 gypsum 324-5 garnierite 409 gaseous 1 habit 32, 61, 111 gases 31 hackly 36 gaylussite 306 175 gedrite 387-8 halite 224-6 gehlinite 368 halloysite 412 geiger counter 46 halogen minerals 202-3 genthite 409 hand-specimen 29-30 geothermal gradient 130 hardness 37-8 INDEX 473 harmotome 438, 442 hypabyssal igneous rocks 122 harsh 31 hypersthene 377 hastingsite 390 hypogene mineralization 139 hatchettine 463 hypothermal deposits 134 hatchettolite 286 haughtonite 402 Iceland spar 289 hausmannite 284-5 idocrase 356-8 haiiyne 432, 435 igneous rock associations 126-7 heavy liquid 40 igneous rock forms 125-6 heavy spar 317 igneous rock textures 123-4 hedenbergite 378, 379 igneous rocks 118, 119-28 heliotrope 430 ignimbrites 125 hematite 263-4 illite 410, 412 hemimorphite 369-70 illite group 412 henwoodite 341 ilmenite 264-5 hepatic cinnabar 244 ilvaite 361-2 Herbert Smith refractometer 86 immersion method (for RI) 87 hercynite 281 immersion oils 87, 89 hessite 233 incident illuminator 115 heteropolar bonding 9-10 inclined illumination 86, 89 heulandite 438, 443 index minerals 130 hexagonal 56, 57, 75-7 indicatrix 91 hexagonal close-packing 11, 13-14 indicolite 373 hiddenite 383 172 high albite - high anorthite 422, 423 indurated talc 405 Highgate resin 464 inosilicates 120, 374-97 holosymmetric class 68 interfacial angle 61 homopolar bonding 9,10-11 interference colours 83, 95, 112, 113 horn lead 308 interference figure 90, 113 horn quicksilver 228 intermediate deposits 128 horn silver 227-8 intermediate magma 122 hornblende series 390-1 internal structure 48-57 hornfels 131 iodine 203 hornstone 431 iodyrite 228 horse-radish 30 iolite 371 hubnerite 344 7 Huttonlocher intergrowths 419 ionic bonding 9-10 hyacinth 352 ionic potential 18 hyalite 431 ionic radius 15, 16 hyalophane 426 ionic size 15 hydrargillite 277 iridescence 28 hydrates 22 iridium 217 hydrocarbons 458-64 iridosmine 217 hydrogrossular 355,356 iron and steel production 203-4 hydromuscovite 412 iron minerals 203-7; a-iron 219; y-iron hydrophane 431 219 hydrothermal alteration 138-9 iron pyrites 247-8 hydroxides 20 iserine 265 hydroxylapatite 336 island arcs 126 hydrozincite 307 island silicates 120 474 INDEX isochromatic curves 97, 98 lava flows 125 isogyres 97, 98 law of constancy of angle 61 isotopes 8 law of rational indices 66-7 isotropic minerals 91, 112 lawsonite 367-8 isotropic section 98 layer lines 50 isotropic substance 90--1 layered intrusion 125 lazurite 432, 436 jacobsite 282 lead glance 235-6 jade 382, 390 lead minerals 180--2 jadeite 382 lead vitriol 319 jamesonite 257-8 leadhillite 310 Japanese law 427 Leitz Jelly refractometer 87 jargoon 352 lenticular 33 jasper 427,430, 431 lepidocrocite 279 jet 460 lepidolite 402-3 Jolly's spring balance 40, 41 lepidomelane 401, 402 leptothermal deposits 136 kaersutite 393, 394 leucite 432, 433-4 kainite 330--1 leucoxene 264, 354 Kalbe light line 116 lievrite 361 kalinite 323 light red silver ore 254, 255 kalsilite 432-3 lignite 459-60 kamacite 219 lime uranite 343 kandites 410 limestone( s) 130, 290 kaolin 410, 411 limonite 280--1 kaolinite 410--12 linarite 182 kaolinite group 410--12 Lindemann glass tube 51 katophorite 393, 394 linnaeite 245 kerargyrite 227-8 liquid 1, 20 kermesite 247 lithium minerals 150 kernite 312 lithographic stone 290 kibdelphane 265 lithomarge 411 kidney ore 263 lithosphere 126, 133 kieselguhr 431 liver opal 431 kieserite 323-4 lizardite 407 kimberlite 127, 223 lopoliths 125 kunzite 383 low albite - low anorthite 422-3 kupfernickel241 lustre 26, 28--9 Kuroko type deposits 140 luxullianite 373 kutnohorite 295 kyanite 357, 359 made 358 macroperthites 419 labradorite 417 magma 118 laccoliths 125 magmatic deposits (Cr, Fe, Ti, Pt) lamellar 32 136 lampadite 269 magmatic deposits (Cu, Ni, Fe, (Pt» langite 326 136 lapis lazuli 436 magnesian limestone 302 Laue method 49, 50 magnesiochromite 281, 284 laumontite 438, 444 magnesioferrite 282 INDEX 475 magnesiosiderite 295 metasomatic zone 131 magnesite 291-2 methylene iodide 42 magnesium minerals 163-4 mica group 397-8 magnetic pyrites 240-1 mica production 399 magnetite 44, 282, 283 micaceous hematite 263 magnetite series 282-3 micanite 399 malachite 307-9 microchemical tests 116-17 malaconite 379 microcline 418 maldonite 212 microcline - low albite series 420 malleable 38 microcosmic salt bead 448 mammilated 33 microindentation hardness tester 116 manganandalusite 358 microperthites 419 manganese deposits 143,200-1 microscope 88, 89-90 manganese minerals 199-201 microscope stage 82, 89 mansjoite 379 mid-ocean ridge 126 mantle 2, 126 miemite302 marbles 290 migmatites 131,357 marcasite 249 milky quartz 428 marganite 278-9 millerite 242 margarite 403-4 Miller's indices 66 marine deposits 128 mimetite 339, 340 marls 130 mineral caoutchouc 463 martite 263 mineral deposits 134-44 mascagnite 316 mineral oil 462 mass spectrometer 46 mineral pitch 462 maximum interference colour 95, 97 mineral sign 99 meagre 31 mineralogy of sedimentary rocks 128 meerschaum 410, 414 minerals 2, 110-15, 118 meionite 436, 437 minium 260-1 melaconite 260 mirabilite 322 melange 132, 133 mispickel 249-50 melanite 355 mitchellite 281 melanterite 326-7 mixtures 2 melilite 368 mobile belts 126 melilite group 368-9 mocha stone 431 melting points 1 Mohs' scale of hardness 37 menaccanite 264, 265 molecular weight 8 Mendeleev 20 molecule 3 menilite 431 molybdena 346 mercury minerals 167-9 molybdenite 250-1 Merensky reef 136 molybdenum minerals 192-3 mesolite 438, 440 molybdic ochre 346 mesoperthites 419 molybdite 346 mesothermal deposits 135 monazite 333-4 metallic bonding 9, 11 monoclinic 55,72-3 metallic lustre 28 monoclinic amphiboles 388-9 metals 7 monoclinic pyroxenes (cpx) 376, metamorphic grade 131 378-83 metamorphic regimes 132-4 montasite 389 metamorphic rocks 118, 130-4 montmorillonite 410, 412-13 476 INDEX montmorillonite group 412-14 Newton's scale of (interference) moonstone 421 colours 94, 96,112-13 morenosite 32R niccolite 241 morion 42R nickel bloom 335 morphology 47 nickel minerals 20R-9 moss agate 431 nickel pyrites 242 mountain cork 396 nickel vitriol 32R mountain leather 396 nickeline 241 mountain wood 396 minerals 183-4 mullite 357, 360 niter 311 mundic 247-R nitrate of potash 311 murchisonite 421 nitrate of soda 310 muriacite 321 nitrates 184 muscovite 39R-9 nitratine 310 muscovy glass 39R nitre 311-12 mylonite 131 nitrogen minerals 184-5 noble serpentine 408 nodular 33 nacrite 410 non-metals 7 nagyagite 232 nontronite 410 nail-head spar 2R9 normal salt 21 naptha 462 normal zoning 423 native amalgam 216 nose an 432, 435 native antimony 220 noumeite 409 native arsenic 219-20 nucleus 3 native bismuth 220 native boric acid 276 objective lens 89 native copper 214-15 oblique extinction 106 native gold 212-13 obtuse bisectrix (Bxo) 10 I native iron 21R, 219 oceanic alkaline rocks 127 native magnesia 259 oceanic tholeiitic rocks 126 native mercury 215-16 ochres 280 native or free elements 23 octahedrite 271-2 native platinum 216-17 ocular 89 native silver 214 odontolite 342 native sulphur 221-2 odour 26, 30-1 native tellurium 221 oil production 177 native zinc 219 oligoclase 417 natroborocalcite 314 olivine 350 natrolite 43R, 439-40 olivine group 350-4 natron 305 omphacite 382 natural gas production 177-R onyx 430, 431 negative uniaxial crystal 93 oolite 290 nemalite 275 oolitic ironstone 293 nepheline 432-3 opal 427, 430 nephe1inite 127 opalescence 28 nephrite 3R2, 390 opaque 29 nesosilicates 120, 350-63 ophicalcite 351, 408-9 neutralization 21 ophiolites 127, 393 neutrons 3 ophitic 123 INDEX 477 optic axes 1()() pearcite 253 optic axial angle 100 pearl spar 302 optic axial plane (OAP) 100 pearly 29 optic axis 91 peat 461 optic normal 101 pectolite 384-5 optical goniometer 61 pegmatitic 123 orangite 353 penninite 406 order of crystallization 121 pentlandite 242-3 ordinary (0) rays 92 periclase 259 ore deposits 134 pericline 421 ore mineral 115-16, 134 pericline law 418 organic sedimentary rocks 130 peridot 350,351 oriental alabaster 289 peridot of Ceylon 373 oriental amethyst 262 periodic classification of elements 20, oriental emerald 262 147-8 oriental topaz 262 periodic table 19, 20 orpiment 245-6 peristerites 419 orthite 367 perovskite 286-7 orthoclase 418 perthites 419 orthoclase - low albite series 420 pert hi tic intergrowths 419 orthoferrosilite 376-7 petrological microscope 89-90,110 orthorhombic 55, 71-2 petzite 233-4 orthorhombic amphiboles 387-8 phacolite 443 orthorhombic pyroxenes (opx) 376-8 phanerozoic ironstones 143 orthosilicates 120 phillipsite 438, 441-2 oscillatory zoning 423 phlogopite 400--1 osmiridium 217-18 phosgenite 308-9 osmium 217 phosphorescence 26, 30 osteolite 338 phosphorite 337 ottrelite 363 phosphorus minerals 185-6 oxidation 22 phyllic zone 139 oxides 20 phyllosilicates 120, 397-416 oxidizing flame 445, 446 physical properties of minerals 26 oxyhornblende 393, 394 picotite 281 ozokerite 463 picrolite 408 piedmontite 366-7 paired metamorphic belts 133 piemontite 366-7 palaeomagnetism 45 piezoelectric minerals 45 210, 217 pigeonite 381 palygorskite 414 pillow lavas 125 palygorskite - sepiolite series 414 pinite 371 pandermite 315 pisolite 290 paragonite 400 pisolites 297 parametral plane 66 pistacite 365, 366 parawollastonite 384 pitchblende 273-4 pargasite 390 plagioclase feldspars 422-6 parting 35-6, 111 plane of symmetry 57 passive margins 126 plane-polarized light (PPL) 81, 90 path difference 48, 83 plasma 430 pea iron ore 280 plate margins 126 478 INDEX plate tectonics 45, 126 protons 3 plateau basalts 127 proustite 254, 255 platform areas 126 pseudobrookite 287 platinum group minerals 209-10 pseudomorph 33 play of colours 27 psilomelane 269, 275-6 pleochroic halo 109 pumpellyite 368 pleochroic scheme 108 pure substance 1 pleochroism 28,107-9,111,116 pycnometer 40, 42 pleonast 281 pyrargyrite 254-5 plumbago 223 pyreneite 355 plumbojarosite 182, 330 pyrite (pyrites) 247-8 plumosite feather ore 258 pyrochlore 286 plutonic igneous rocks 123 pyroclastic rocks 125 point of fusion 446 pyroelectric minerals 45 point of oxidation 446 pyrolusite 268 point of reduction 447 pyrometasomatic deposits 137-8 polarizer 89-90, 116 pyromorphite 339 pole (to a face) 63 pyromorphite series 338--9 polianite 268 pyrope 354, 356 polishing hardness 116 pyrophyllite 404-5 polybasite 253 pyroxene group 374-83, 387 polyhalite 323 pyroxenoid group 383-6 polymorph 34 pyrrhotine 240--1 polytypes 34-5, 410 pyrrhotite 44, 240--1 ponite 295 porcelain jasper 431 qualitative analysis 23--4 porphyritic 123 quantitative analysis 23, 24 porphyry copper deposits 138--9 quartz 49, 178,427-9; a-quartz (low porphyry molybdenum deposits 139 quartz) 427; ~-quartz (high quartz) porphyry tin deposits 139 427 positive uniaxial crystal 93 quicksilver 215-16 potash alum 323 potash mica 398 radelerz 257 potassic zone 138 radiating 33 potassium minerals 152-3 radioactive minerals 45-6 pots tone 405 radioactivity 45-6 powder camera 51 radiometric age 46, 146 powder method 49, 50--1 195 prase 430 radius ratio 17 Precambrian banded ironstone rare earth (REE) minerals 137, 175-6 formations (BIF) 142-3 rasorite 312 precious garnet 355 ray velocity surface 90, 91 precious opal 431 rays 81 precious serpentine 408 reaction 23 prehnite 410, 416 reagents 23 priceite 315 realgar 244-5 principal refractive indices 91 red antimony 247 principal section (of ellipse) 93, 100 red bole 412 prismatic 32 red oxide of copper 258--9 propylitic zone 138 red oxide of lead 260--1 INDEX 479 red oxide of zinc 259-60 rough 31 reddle 263 rubellite 373 redox reaction 22 rubicelle 282 redruthite 234 ruby 262 reducing flame 445, 446-7 ruby copper 258 reduction 22 ruby silver group 254-5 REE 175 ruby-spinel 282 reflectance 116 rudaceousrocks 130 reflected light 83 ruthenium 218 reflected light techniques 115-16 rutile 266-8 reflecting goniometer 61 reflection planes 57 sabkha 141, 226 refraction 83, 84 saccharoidal 33 refractive index (RI) 83 sahlite (salite) 378, 379 refractometers 83 sal-ammoniac 226-7 regional metamorphism 131,132 saline 30 regional metamorphism in orogenic salt domes 226 belts 132 saltpetre 311 reinite 344 salts 20 relative retardation 94 sanidine 418 relief (mineral) 111-12 sanidine - high albite series 420 remolinite 229 sapphire 262 reniform 33 sard 430 rensselaerite 405 sardonyx 431 residual bonding 9, 14-15 sassolite 276 residual deposits 143--4 satin spar 289, 324 resinous 29 saussuritization 364 reticulated 32 scaly 32 reversed zoning 423 scapolite 436-7 rhenium 202 scheelite 345 rhodium 210, 218 schiller 27 rhodium gold 212 schillerspar 377 rhodochrosite 294-5 schorl 372, 373 rhodonite 200, 385-6 schriebersite 219 rhomb spar 302 scintillometer 46 ribbon jasper 431 scolecite 438, 440--1 richterite 393 scotch pebble 431 riebeckite 291-2 second-order spectrum 95-6 rifting 127 secondary twinning 36 ring silicates 120 sectile 38 ripodolite 406 sedimentary rock textures 129 rock crystal 428 sedimentary rocks 118, 128-30 rock meal 289 seelandite 327 rock milk 289 selenite 324 rock phosphates 337 minerals 197-8 rock -salt 224-6 senarmontite .265-6 rocks 2, 118 sensitive tint plate 97 rodingites 356 separating funnel 43 rose quartz 428 sepiolite 410, 414 rotation method 49, 50 septechlorites 406 480 INDEX sericite 398, 420 sphene 353-4 serpentine 407-9 sphericity 129 set of faces 57 spinel 206, 281 shadow method (for RI) 89 spinel group 281 sheet silicates 120, 397-416 spinel series 281-2 shield areas 126 spinel-ruby 282 shining 29 splendent 29 siderite 293-4 spodumene 382-3 siderophyllite 401, 402 staffelite 337 silica group 427 stalactites 289 silicate minerals 119-20, 178, 348 et stalagmites 289 seq. stannine 239 silicate of zinc 369 stannite 239 silica-undersaturated alkaline magmas stassfurtite 315 124 staurolite 362-3 siliceous sinter 431 steatite 405 minerals 178 stellate 33 silky 29 stephanite 253-4 sillimanite 357, 359-60 stereogram 63, 78, 79-80 sills 125 stereographic net 64 silver amalgam 216 stereographic projection 62-4 silver glance 232-3 stibnite 246 silver minerals 156-7 stilbite 438, 443-4 single-chain silicates 120, 374-86 stilpnomelane 404 skarn 131, 137 stinks tone 290 skolite 400 stishovite 427 smaltite 252 stocks 125 smectites 412 stockwork and disseminated deposits smithsonite 295-6 (Cu,~o,Sn) 138-40 smoky quartz 428 straight extinction 106 smooth 31 stratabound deposits 140-1 soapstone 405 stratiform oxide deposits 140-1 sodalite 432, 434-5 stratiform sulphide deposits 140-1 sodalite group 432, 434-7 streak 26, 28, 38 soda-nitre 310-11 streak-plate 28 sodium carbonate bead 449 stream tin 270 sodium minerals 150-2 strontianite 299-300 solid 1,31 strontium minerals 161 sorosilicates 120, 363-70 sub-atomic particles 3 sour 30 subduction zone 126 space lattice 48, 52, 54 sublimate 1,449-50 spartalite 259-60 submetallic lustre 28 spathose iron 293 sub-seafloor metamorphism 132 specific gravity bottle 40, 42 substage diaphragm 90 specific gravity (SG) 39-40 sub transparent 29 spectrometer 24 subvitreous 28 specular iron ore 263 sulphur minerals 196-7 sperrylite 248 sulphurous 31 spessartite 354 sunstone 421 sphalerite 237-8 supergene enrichment 143 INDEX 481 surface tension 39 tile ore 258 swift sludent polarizing microscope 88 tin minerals 178-80 sylvanite 251-2 tin pyrites 239 sylvine 226 tin white cobalt 252 sylvite 226 tinca1312,313 symbol 3 tincalconite 313 tins tone 270 tabular 32 titanium minerals 172-4 tabular spar 383 toad's eye tin 270 taenite 219 topaz 360-1 talc 405-6 topazolite 355 talc production 406 torbanite 460 tangent ratio 66 torbernite 342-3 tantalite 287 tourmaline 372-3 tantalite-niobite 287 translucency 26, 29-30 minerals 183-4 transmitted light 81 tarnish 28 transparency 26, 29-30 taste 26, 30 travertine 132, 289 taylorite 316 tremolite 389-90 tektosilicates 120, 416-44 trenches 126 telethermal deposits 136 trevorite 282 telluric bismuth 231-2 triclinic 55, 73 tellurite 272-3 tridymite 427, 429-30 tellurium minerals 198-9 trigonal 56, 73-4 tenacity 38 tripestone 321 tennantite 255-6 troilite 219 tenor (of ore) 134 trona 305-6 tenorite 260 troastite 353 tephra 125 tschermakite 390 tephrite 125 tube tests 449-50 terrigenous rocks 129 tufa 130 tetrabromoethane 42 tuffs 125 tetradymite 231-2 Tully refractometer 86 tetragonal 55, 70-1 tungsten minerals 193-4 tetrahedrite 255-6 tungstic ochre 274 tetrahedrite series 255-6 tungstite 274 thenardite 316 turgite 263 theory of valency 7 turquois 341 thermal metamorphism 131 341-2 thermonatrite 304-5 twinning 115, 116,418 thin section 89,109-10 thinolite 289 uintaite 463 third-order spectrum 96 ulexite 314 tholeiites 127 ultrabasic magma 121 thomsonite 438, 441 unctuous 31 thorianite 274 uniaxial indicatrix 91 thorite 352-3 unit cell 48, 50, 52-3 minerals 176 unit cell types 55-7 thulite 364 unstable isotopes 46 tiger's eye 392 uraconite 331 482 INDEX uralite 390 Westphal balance 40, 43 uralhized 390 wheel ore 256, 257 uranium minerals 194-5 white arsenic 265 urao'305 white iron pyrites 249 uvarovite 354, 356 white lead ore 256--7, 300 white nickel 252 valency 7 white of a higher order 96 valentinite 266 white vitriol 327 Van der Waals bonding 9,14-15 wilhelmite 353 vanadinite 339 wille mite 283, 353 minerals 182-3 wiry 33 variegated copper ore 234-5 withamite 366 veins 135, 141 witherite 298--9 venite 361 wolfram 344 vermiculite 410, 413-14 wolframite 344, 345 vernier 89 wollastonite 383-4 vesicular 123 wood 459 vesuvianite 356 wood opal 431 Vickers hardness number 116 wood tin 270 viridine 358 wulfenite 345-6 vishnevite 432 Wulff net 64 vitrain 461 wurziIlite 463 vitreous 28 vitreous copper ore 234 xanthocroite 239-40 vivianite 335 xanthophyllite 404 volatiles (in coals) 460 xenotime 332-3 volcanic massive sulphide deposits X-ray diffractometer 48,117 140--1 X-ray diffraction 24, 48, 50 volcanoes 125 X-ray fluorescence 24 vulpinite 320 zaratite 306 wackes 129, 130 zeolite group 437-44 wad 207, 269 zinc minerals 164-7 Walker's steelyard balance 40, 41 zincite 259-60, 283, 353 waringtonite 326 zinnwaldite 403 water content (of coals) 460 zippeite 331 water of crystallisation 22 zircon 351-2 water sapphire 372 zirconite 352 wathlingenite 323 minerals 174 wavelength (of light) 81-2 zoisite 364; a-zoisite364; ~-zoisite 364 waveIlite 342 zone 57 waves 81, 82 zone axis 57 websterite 331 zoning 115,423