DOCSLIB.ORG

GUIA DE IDENTIFICACIÓN DE MINERALES Lustre: Metálico

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
GUIA DE IDENTIFICACIÓN DE MINERALES Lustre: Metálico GUIA DE IDENTIFICACIÓN DE MINERALES Lustre: metálico / submetálico / no metálico Lustre Metálico Generalmente con raya de color, opacos RAYA DUREZA COLOR REMARKS NOMBRE S.G. 2.0 Steel GRAPHITE Black 1 Basal cleavage; Soft, marks on paper, greasy feel. gray GRAFITO Used in lubricants and pencils. S.G. 4.8 PYROLUSITE Iron-black 1-2 Black Radiating fibers, granular masses, or dendritic; sooty. PYROLUSITA An ore of manganese. S.G. 3.3 to 4.0 Yellow Your basic rust. Many forms and lusters. Occurs as Yellow LIMONITE 1 to 5 brown to flattened crystals, massive, reniform, or stalactitic. brown LIMONITA black Common secondary mineral in rocks and soils. An ore of iron. S.G. 4.8 to 5.3 Many forms and lusters (can also occur in sub- Red metallic to non-metallic forms). Can be massive, Steel HEMATITE brown to 1 to 6.5 radiating, botryoidal, and micaceous. The crystalline gray HEMATITA Indian red (metallic and sub-metallic) varieties are generally harder than the earthy (non-metallic) varieties. An ore of iron. S.G. 7.6 Perfect cubic cleavage (3 @ 90°); Occurs in cubes; Gray 2.5 Gray GALENA may be massive or granular; heavy. The most common ore of lead. S.G. 10 to 12 Silvery Hackly fracture, easily distinguished from galena by Light gray white, SILVER 2.5 lack of cleavage. Malleable and ductile. Used in to silver tarnishes PLATA coinage, fillings for teeth, jewelry, silverplate, to black photography, wires. S.G. 19.3 Pale to Hackly fracture. Malleable and ductile. Used in GOLD Yellow 2.5 to 3.0 golden coinage, fillings for teeth, jewelry, goldplate. ORO yellow Extensive use in computer industry as non-corrosive contact points for silicon chips. Bronze, S.G. 4.9 to 5.4 tarnishes Commonly called "peacock ore" because of the Gray to BOURNITE 3.0 to dark purple shine when it tarnishes. black BOURNITA blue and A common source of copper. purple S.G. 8.5 to 9.0 Copper Copper Malleable and ductile. Used in coins, pipes, wires, KOPER 3.0 red red gutters, cooking utensils, pots and pans, jewelry, COBRE decorative items. Greenish- 4 Brass S.G. 4.3 CHALCOPYRITE black yellow The distinctive buttery yellow color is often tarnished CALCOPIRITA purple or gray; yellower and softer than pyrite. An ore of copper. S.G. 4.6 Distinctive chocolate brown streak. Commonly occurs Black to as stratabound deposits in dunite segregations in CHROMITE Chocolate 5.5 dark ultramafic rocks, and as podiform masses in brown brown serpentinite. Used in stainless steel, high CROMITA temperature alloys, and as refractory bricks. The ore of chromium. S.G. 5.2 Conchoidal fracture. Strongly magnetic. Often called MAGNETITE Black 6 Black "lodestone." Common accessory mineral occurring as MAGNETITA disseminated grains in mafic igneous rocks. An ore of iron. S.G. 5.0 Often in cubic crystals. Can be massive, granular. Black to Pale PYRITE 6 Common name: "Fool's gold." Commonly alters to greenish brass PIRITA limonite. Sometimes mined as a source of sulfur. LUSTRE: Sub metálico RAYA DUREZA COLOR REMARKS NOMBRE S.G. 3.3 to 4.0. Your basic rust. Many forms and lusters. Occurs as Yellow- Yellow to LIMONITE 1 to 5.5 flattened crystals, massive, reniform, or stalactitic. brown dark brown LIMONITA Common secondary mineral in rocks and soils. An ore of iron. S.G. 4.8 to 5.3 Many forms and lusters (can also occur in sub-metallic Red to non-metallic forms). Can be massive, radiating, brown to Red, HEMATITE 1 to 6.5 botryoidal, and micaceous. The crystalline (metallic Indian HEMATITA vermillion and sub-metallic) varieties are generally harder than red the earthy (non-metallic) varieties. An ore of iron. LUSTRE: No-metálico. Raya incolora o de color muy claro Dureza: < 2.5 / 2.5 a 3.5 / 3.5 a 5.5 / >5.5 Dureza: < 2.5 (se marca con la uña del pulgar) PATRON D SP. DUREZA COLOR REMARKS NOMBRE RUPTURA GR. Easily scratched with fingernail. Flexible but not elastic; foliated; slick or soapy feeling. Typical luster: Good White, pearly to waxy. Used on baby's butts, TALC 1 cleavage in green, 2.7 and in paints, ceramics, rubber, TALCO 1 direction pink insecticides, and paper. Variety SOAPSTONE can be carved into ornamental shapes and items. Earthy; clayey odor. Earthy to dull luster. A swelling clay, used to stop MONTMOR- White, leaks in soils, rocks, dams, and 1-2 Fracture 2-3 ILLONITE tan, gray basement walls. Due to its excellent MONTMORILONITA water-retention properties, it is also used as a soil additive and kitty litter. Not truly a mineral (lacks fixed Yellow chemical composition). Earthy to Uneven BAUXITE 1-3 brown to 2-3 pisolitic (large round grains). Earthy, fracture BAUXITA red dull to waxy lusters. The most important ore of aluminum. Your basic rust. Many forms and Yellow, lusters. Occurs as flattened crystals, Conchoidal 2.7- LIMONITE 1-5.5 brown to massive, reniform, or stalactitic. fracture 4.3 LIMONITA black Common secondary mineral in rocks and soils. An ore of iron. Many forms and lusters (can also occur in metallic forms). Can be massive, radiating, botryoidal, and Brown, 4.8 Irregular micaceous. The crystalline (metallic HEMATITE 1-6 red, steel to fracture and sub-metallic) varieties are HEMATITA gray 5.3 generally harder than the earthy (non-metallic) varieties. An ore of iron. Characteristic bright yellow color; when small pieces are held in the hand close to the ear, crackling can Conchoidal be heard due to rapid, uneven SULFUR 1.5-2.5 to uneven Yellow 2.1 thermal expansion. Pearly, waxy, AZUFRE fracture resinous, to dull lusters. Used to make sulfuric acid, fertilizers, insecticides, explosives (kaBoom), and medicines. 2 No White, 2.6 Earthy; clayey odor; absorbs KAOLINITE macroscopic often moisture so rapidly that it will stick to KAOLINITA cleavage colored by the tongue. Earthy to dull lusters. impurities Used in refractories, china, pottery and as a filler in paper. Also used in soft-serve ice cream to retard melting on hot summer days. As crystals and broad cleavage flakes with waxy to pearly to vitreous Colorless, lusters (selenite variety); as compact white, fine-grained masses showing no 1 direction, gray, visible cleavage, earthy to dull to perfect, 2 GYPSUM 2 gray- 2.3 waxy lusters (alabaster variety); as directions, YESO brown, fibers with satiny luster (satin spar good pink variety). Large crystals somewhat reddish flexible, but not elastic. Used to make Plaster of Paris and sheetrock wallboard (drywall). Thin sheets are flexible, but not elastic. Lusters typically resinous, waxy, vitreous or dull. A common Dark alteration mineral found in mafic CHLORITE green to 2-2.5 1 direction 2.7 igneous rocks (alteration of the green- ferromagnesian minerals to chlorite black CLORITA results in the greenish tint common to altered basalt, and the re-naming of the rock "greenstone." Platy or fibrous; waxy luster when Wavy, massive, satiny luster when fibrous Green SERPENTINE 2-3 uneven 2.5 (asbestos variety). Used as an and white SERPENTINITA fracture insulating material against heat and electricity. In granular cleavable masses or cubic crystals. Soluble in water; salty White taste. Typical lusters: vitreous, waxy, 3 directions, when 2.1 dull. Common salt: used as a source HALITE 2.5 perfect, pure; may to of sodium compounds and HALITA cubic be red, 2.3 hydrochloric acid; used to salt blue, pink highways in winter; used as a seasoning and preservative in food. Common silicate mineral in felsic igneous rocks and low to medium grade metamorphic rocks. In foliated masses and scales. Transparent, flexible and elastic sheets. Vitreous Pale to pearly luster. Used as insulating 1 direction brown, material in electrical appliances and MUSCOVITE MICA 2.5 2.8 perfect green, as a fireproofing material. Also, MUSCOVITA yellow Muscovite was used as windows before the invention of plate glass, was common as the rear window in early model convertible cars, and is still used as the front view-screen in many "fire-view" type wood stoves. Common ferromagnesian silicate mineral in felsic to intermediate Dark igneous rocks and low to medium BIOTITE 1 direction, brown, grade metamorphic rocks. In MICA 2.5 to 3.0 3.0 perfect green to irregular foliated masses and scales. black Translucent, somewhat flexible and BIOTITA elastic sheets. Pearly to vitreous luster. Forms hexagonal crystals. LUSTRE: No-metálico Raya Incolora o de Color Claro Dureza: 2.5 a 3.5 (no se puede marcar con uña ni con moneda de cobre) PATRON D SP. DUREZA COLOR REMARKS NOMBRE RUPTURA GR. Your basic rust. Many forms and lusters. Yellow, Occurs as flattened crystals, massive, Conchoidal 2.7- LIMONITE 1-5.5 brown to reniform, or stalactitic. Common fracture 4.3 LIMONITA black secondary mineral in rocks and soils. An ore of iron. Many forms and lusters (can also occur in metallic forms). Can be massive, 4.8 radiating, botryoidal, and micaceous. The Irregular Brown, red, HEMATITE 1-6 to crystalline (metallic and sub-metallic) fracture steel gray HEMATITA 5.3 varieties are generally harder than the earthy (non-metallic) varieties. An ore of iron. Platy or fibrous; waxy luster when Wavy, Green and massive, satiny luster when fibrous SERPENTINE 2-3 uneven 2.5 white (asbestos variety). Used as an insulating SERPENTINITA fracture material against heat and electricity. In granular cleavable masses or cubic crystals. Soluble in water; salty taste. White Typical lusters: vitreous, waxy, dull. 3 directions, when pure; 2.1 Common salt: used as a source of HALITE 2.5 perfect, may be to sodium compounds and hydrochloric HALITA cubic red, blue, 2.3 acid; used to salt highways in winter; pink used as a seasoning and preservative in food.
Load more

Recommended publications
  • Christie's Presents Jewels: the Hong Kong Sale
    FOR IMMEDIATE RELEASE October 28, 2008 Contact: Kate Swan Malin +852 2978 9966 [email protected] CHRISTIE’S PRESENTS JEWELS: THE HONG KONG SALE Jewels: The Hong Kong Sale Tuesday, December 2 Christie’s Hong Kong Hong Kong – Christie’s announces the fall sale of magnificent jewellery, Jewels: The Hong Kong Sale, which will take place on December 2 at the Hong Kong Convention and Exhibition Centre. This sale features an exquisite selection of over 300 extraordinary jewels across a spectrum of taste and style, from masterpieces of the Belle Époque to contemporary creations, and from the rarest of white and coloured diamonds to important coloured stones. COLOURLESS DIAMONDS Leading the auction is a rare pair of D colour, Flawless diamonds weighing 16.11 and 16.08 carats (illustrated right, estimate: HK$40,000,000-60,000,000 / US$5,000,000-8,000,000). These marvellous stones are also graded ‘Excellent’ for polish, symmetry and cut grade, making them exceedingly rare for their superb quality. Classified as Type IIa, these diamonds are the most the chemically pure type of diamonds known, with no traces of the colorant nitrogen. The absence of this element, seen in 98% of diamonds, gives these stones a purity of colour and degree of transparency that is observed only in the finest white diamonds. The modern round brilliant cut is the diamond’s most basic and popular shape, as it allows the potential for the highest degree of light return. But more importantly, the round diamond sustains the highest value as its production requires riddance of the greatest amount of diamond rough.
    [Show full text]
  • The Red Diamond
    The Red Diamond John Fitzgerald Rob Floyd The Red Diamond Text and image copyright © John Fitzgerald and Rob Floyd 2012 Thalassa by Louis MacNeice is reproduced by kind permission of David Higham literary, film and TV agents. The authors would also like to thank Penguin Books for permission to quote from King Arthur and His Knights of the Round Table by Roger Lancelyn Green, and Colin Wilson for the phrase, ‘Imagination is the Herald of Change’. Contents Welcome The Sulphurous Heart Seekers in the Sunrise Britain is Our Playground Daughters of the Revolution The Arch of Constantine The Lantern Bearer Temenos The Mind and the World The Room of the Golden Dance Glittering Prize Rebel Angels Useful Idiots Panache, Power and Pride Visions and Ruins The God Abandons Antony The Red Diamond The Far Wall Welcome Man is in love with what abandons him. That’s the starting point of every quest. Meister Eckhart ******* Hello, thank you and welcome to The Red Diamond. We hope it stirs your imaginations and that you enjoy it in every way. The Red Diamond is essentially an Art Book, with Rob’s illustrations playing as central a role in the story’s unfolding as does my text. Our intent has not been so much to say, ‘this happened here, that happened there and here’s the picture to prove it’, but rather to allow words and pictures to come together in the hope of creating new contemplative spaces – evocative spaces – spaces of growth, possibility and playful creative change. The text tends therefore to concentrate more on atmosphere and mood than the adoption of a purely realistic approach to the story’s development.
    [Show full text]
  • Compilation of Reported Sapphire Occurrences in Montana
    Report of Investigation 23 Compilation of Reported Sapphire Occurrences in Montana Richard B. Berg 2015 Cover photo by Richard Berg. Sapphires (very pale green and colorless) concentrated by panning. The small red grains are garnets, commonly found with sapphires in western Montana, and the black sand is mainly magnetite. Compilation of Reported Sapphire Occurrences, RI 23 Compilation of Reported Sapphire Occurrences in Montana Richard B. Berg Montana Bureau of Mines and Geology MBMG Report of Investigation 23 2015 i Compilation of Reported Sapphire Occurrences, RI 23 TABLE OF CONTENTS Introduction ............................................................................................................................1 Descriptions of Occurrences ..................................................................................................7 Selected Bibliography of Articles on Montana Sapphires ................................................... 75 General Montana ............................................................................................................75 Yogo ................................................................................................................................ 75 Southwestern Montana Alluvial Deposits........................................................................ 76 Specifi cally Rock Creek sapphire district ........................................................................ 76 Specifi cally Dry Cottonwood Creek deposit and the Butte area ....................................
    [Show full text]
  • Lab 2 – Mineral Properties and Non-Silicate Minerals
    LAB 2: MINERAL PROPERTIES AND NON-SILICATE MINERALS Lab Structure Yes – review concepts from Labs 1 and 2 in preparation Recommended additional work for Test 1 Required materials Mineral ID kit, Mineral Kits 1 and 2, pencil Learning Objectives After reading this chapter, completing the exercises within it, and answering the questions at the end, you should be able to: • Describe mineral lattices and explain how they influence mineral properties. • Categorize minerals into groups based on their compositions. • Describe some of the important techniques for identifying minerals. • Identify and describe the physical properties of a range of non-silicate minerals in hand sample. • Discuss the economic uses of non-silicate minerals. Key Terms • Cation • Phosphate • Anion • Colour • Silicate • Streak • Non-silicate • Lustre • Native element • Hardness • Sulphide • Crystal habit • Oxide • Cleavage • Hydroxide • Fracture • Sulphate • Conchoidal fracture • Carbonate • Specific gravity • Halide Minerals are all around us: the graphite in your pencil, the salt on your table, the plaster on your walls, and the trace amounts of gold in your computer. Minerals can be found in a wide variety of consumer products including paper, medicine, processed foods, cosmetics, electronic devices, and many more. And of course, everything made of metal is also derived from minerals. 49 | Lab 2: Mineral Properties and Non-Silicate Minerals As defined in the introductory chapter, a mineral is a naturally occurring combination of specific elements arranged in a particular repeating three-dimensional structure (Figure I4). “Naturally occurring” implies that minerals are not artificially made. Many minerals (e.g., diamond) can be made in laboratories, but if they can also occur naturally, they still qualify as minerals.
    [Show full text]
  • Lab 2: Mineralogy
    Lab 2: Mineralogy Reading Understanding Earth, Ch. 3, and Appendix 4 Objectives • To learn how minerals are classified • To learn the common properties of mineral groups • To identify common minerals found in the Earth’s crust Introduction The crust of the Earth is made up of a variety of different rocks. Each type of rock is formed from an assemblage of minerals. Minerals are the basic "building blocks" of rocks, and the recognition of common minerals and rocks is an essential part of the study of geology. A mineral is defined as a chemical element or compound that is a naturally-occurring crystalline solid and is formed as a result of inorganic processes. The terms "rock" and "mineral" are often erroneously used interchangeably. It is important, therefore, to emphasize the key differences between these materials. A mineral is a substance formed by nucleation and growth in an “orderly, three dimensional array.” It is relatively continuous and homogeneous, with a set chemical composition or range of compositions. A rock is an aggregate of minerals with possible wide variations in chemical compositions and crystal structures. A mineral can be represented by a chemical formula, while a rock cannot. Figure 2.1 The difference between a mineral and a rock. Left: The mineral garnet. Right: The rock eclogite, made up of garnet and clinopyroxene. Although there are over 3000 minerals that have been discovered, fewer than 30 make up the bulk of the earth's crust. These are called the rock-forming minerals, and are the ones you are most likely to encounter in the rocks around you.
    [Show full text]
  • 2012 HK Christies Coloured Stones
    Christie’s Expert Lecture Sunday 27th May 2012 Colourful Treasures of Nature: Ruby, Sapphire, Emerald & Pearls presented by Dr. Michael S. Krzemnicki Swiss Gemmological Institute SSEF Photos © M.S. Krzemnicki, SSEF, except where indicated otherwise Coloured gemstones are formed during large-scale geological processes which have shaped the world as we know it today...! Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons! 1! Kashmir sapphire Foto: Baltoro-Gletscher, Karakorum; Guilhem Vellut via, WikiCommons! The collision of the Indian plate with the Eurasian continental plate has produced some of the most important sources for coloured gems, such as the sapphires from Kashmir and the sapphires and rubies from Burma, and many more.! 2! Inclusions should not only be considered as imperfections, ! but rather as individual proof and fingerprint of the age and formation conditions of a gemstone!! Garnier et al. 2006! Foto:H.A. Hänni, SSEF! © Swiss Gemmological Institute SSEF Inclusions may also be very characteristic for a specific provenance of a gemstone, thus being a valuable proof for its origin.! Blue colour zone in a ruby from Mong Hsu (Burma)! © Swiss Gemmological Institute SSEF 3! These sources for coloured stones are often known since historic times and their gems have been treasured over centuries for their beauty and rarity.! Bagan, Burma © P. Boegli, Flickr.com! © Swiss Gemmological Institute SSEF Where do the stones come from... © Swiss Gemmological Institute SSEF 4! Mwarasi'ruby'deposit,' Tanzania' © Swiss Gemmological Institute SSEF Near Mahenge, Central Tanzania: spinel & ruby mines © Swiss Gemmological Institute SSEF 5! Matombo (Uluguru Mountains)" Morogoro Province! Foto: W. Balmer, 2009! The Umba valley, Northern Tanzania © Swiss Gemmological Institute SSEF 6! The varieties of Corundum: Ruby, Sapphire, & Fancy sapphires: Trace elements resulting in a wide range of attractive colours including padparadscha © Swiss Gemmological Institute SSEF Sapphire 7! Kashmir sapphire The Kashmir sapphire mines from Tom D.
    [Show full text]
  • The Duncan to Mayco Conversion Chart
    TO CONVERSION CHART CC135 Lake Blue .......................UG72 Wedgewood Blue CC203 Neon Chartreuse ....................UG218 Pear Green CC136 Marlin Blue ...........................UG94 Pansy Purple CC204 Neon Orange......................UG85 Orange Sorbet CC137 Regency Purple.....................UG87 Regal Purple CC205 Neon Green ............................UG218 Pear Green CC140 Morocco Red .................................UG10 Crimson CC206 Neon Red .................................UG208 Fame Red AG401 Marbled Celadon ...................EL131 Turtle Shell CC141 Light Yellow .........................UG46 Bright Yellow AG402 Turquoise Haze ...................EL136 Lapis Lagoon CC142 Canary Yellow ......................UG46 Bright Yellow AG403 Ocean Mist ...............................EL103 Sea Spray CC143 Yellow Orange ..................UG203 Squash Yellow AG404 Winter Fog ...........................EL124 Stormy Blue CC144 Burnt Orange ...................UG203 Squash Yellow AG405 Smoke Stack ..........................EL101 Oyster Shell CC145 Indian Red ..................................UG31 Chocolate CN012 Bright Straw* ............................SC24 Dandelion AG406 Aged Moss .........................EL125 Sahara Sands CC146 Purple ........................................UG93 Wild Violet CN022 Bright Saffron* ..........................SC24 Dandelion AG408 Oyster Shell ................... EL140 Toasted Almond CC148 Deep Turquoise .......................UG19 Electra Blue CN052 Bright Tangerine* ...........SC50 Orange Ya Happy AG409
    [Show full text]
  • Zircon - a Very Old Gemstone 鋯鋯石 - 由來已久的寶石 Prof
    Zircon - A Very Old Gemstone 鋯鋯石 - 由來已久的寶石 Prof. Dr Henry A. Hänni（亨瑞 翰尼）, FGA, SSEF Research Associate Fig. 1 A selection of zircons of various origins. The greyish cabochon is a cat’s eye weighing 4.5 cts. 一組不同產地的鋯石。灰色調的素面鋯石貓眼為4.5 cts。 Photo © H.A.Hänni 本文提及兩種含鋯的常見寶石材料 — 鋯石和 hafnium and lead, Zircons usually contain traces 氧化鋯。作者詳述了鋯石的特徵 — 獨特的脫 of the radioactive elements uranium and thorium. 晶法，它不但影響寶石的物理特性，而且間接 As these decay, naturally, over millions of years, 地形成星光或貓眼效應；同時描述鋯石的產地 the alpha particles released gradually destroy 及顏色處理，並簡述氧化鋯的特性。 the zircon crystal lattice, a process that is called metamictisation. The degree of metamictisation Introduction depends on the concentraton of radioactive The mineral Zircon has quite a simple chemical elements and the duration of irradiation. Fig. 3 formula, ZrSiO4; a zirconium orthosilicate. shows a qualitative ED-XRF analysis, showing the Zircons are magnificent gemstones with a high elements present in a metamict green gem from lustre, and they occur in different colours, such Sri Lanka. as white, reddish, yellow, orange and green (Fig. 1). Coloured varieties of zircon may appear in the market as hyacinth (golden to red-brown), jargon (colourless to grey and smoky), metamict (green) or starlite (blue). These terms including “matara diamond” are largely obsolete and only used in older books. Zircons from Cambodia can be heated to blue or colourless. In the early 20th century heated colourless zircons were the perfect Fig. 2 A collection of rough zircons from various deposits: On substitute for diamonds. the left Mogok (Burma), on the right Tunduru (Tanzania), granite sample with zircon, Madagascar (5 cm across).
    [Show full text]
  • Mineral Properties and Identification
    UNIVERSITY of SOUTH AUSTRALIA School of Natural and Built Environments, Mawson Lakes Mineral properties and identification Text reference: Marshak, S. (2012) Earth: Portrait of a Planet. 4th edition, WW Norton & Co., Chapter 5. INTRODUCTION This practical is intended to introduce you to the physical properties of minerals and the ways in which those properties are used in the practical identification of mineral specimens. On completion of this practical, you should be able to: 1. Determine the physical properties of minerals, such as hardness, cleavage and lustre; 2. Distinguish between mineral cleavage, crystal faces and fracture surfaces, and recognise the various types of cleavage; 3. Use a mineral identification key or set of mineral identification tables to successfully identify some common rock-forming minerals. PHYSICAL PROPERTIES OF MINERALS What is a mineral? • Naturally occurring; • Solid and crystalline; • Orderly arrangement of atoms; • Definable chemical composition; • Usually inorganic. Each mineral has a unique set of physical properties that allows it to be identified. Together, two or three of these properties may be diagnostic for a given mineral. Some of the most commonly used properties are: 1. COLOUR – See text page 116; Fig. 5.11a. The colour of a mineral is one of its most obvious features. However, it is generally not a diagnostic feature. Some minerals can be identified by their colour, but many minerals can show a variety of colours in different specimens. 2. STREAK – See text page 117; Fig. 5.11b. While it is common practice in the laboratory to use a streak plate as described in the text, it is more usual in the field to scratch the mineral with the point of a knife blade or geological hammer (while also evaluating mineral hardness) and to rub the thumb over the powdered mineral to obtain its streak.
    [Show full text]
  • Lecture 3 C.M
    SGL 101: MATERIALS OF THE EARTH Lecture 3 C.M. NYAMAI ________________________________________________________________________ LECTURE 3. 3.0 PHYSICAL PROPERTIES OF MINERALS 3.1 INTRODUCTION Welcome to lecture 3. In lecture 2 we looked at the elementary principles of crystallography and illustrated how the symmetry elements of the crystals are deduced. By definition we have shown that crystals are crystalline materials, and by extension are also minerals. In this lecture we shall introduce the elementary principles of Mineralogy. Minerals and consequently mineralogy- which is the science of minerals, is extremely important to economics, aesthetics, and science. Economically, utilization of minerals is necessary if we are to maintain anything like our current standard of living. Aesthetically, minerals shine as gems and enrich our lives, especially as we view them in the museum displays. Scientifically, minerals comprise the data bank from which we learn about our physical earth and its constituent materials. In addition, the basic principals in mineralogy are applied in other disciplines, such as agricultural sciences, the material sciences (ceramic engineering and metallurgy) and even medical science. In this lecture we shall study the major physical properties of minerals and show you how to identify mineral species using these properties. OBJECTIVES At the end of this lecture you should be able to: a). Define a mineral b). Demonstrate an understanding of the identifying characteristics of a mineral. c). Recognize the characteristic physical properties such as cleavage, lustre, density and hardness, of common minerals. d). Determine the physical properties of various mineral species. 24 SGL 101: MATERIALS OF THE EARTH Lecture 3 C.M.
    [Show full text]
  • Gemstone Enhancement and Its Detection in the 2000S
    GEMSTONE ENHANCEMENT AND ITS DETECTION IN THE 2000S Shane F. McClure, Robert E. Kane, and Nicholas Sturman Advances in technology and increased demand for lower-priced gem materials contributed to the proliferation of new treatments throughout the first decade of the 2000s. The developments that made the most difference were the diffusion treatment of corundum with beryllium, diffusion of copper into feldspar, clarity enhancement of ruby and diamond, and heat treatment of diamond, ruby, and sapphire. Gemological laboratories and researchers have done their best to keep up with these treatments, and the jewelry trade has struggled with how to disclose them. This article summarizes these developments and the methods used to identify the various enhancements. nother decade has passed since we reviewed invest in more sophisticated instrumentation, some- the events of the 1990s as they pertained to times at great expense. For the frontline laboratories, A gemstone enhancements and their detection being a good gemologist is no longer good enough. (McClure and Smith, 2000). At that time, we You must also have training in the earth sciences observed that the issue of disclosure (and, especially, and analytical instrumentation to function effective- the failure to disclose) had caused major upheaval in ly in such an environment. Now more than ever, the all areas of the jewelry industry. We ended that ret- gemologist in the trade must be able to recognize rospective article by stating there would be no end to when a stone requires more advanced testing. fresh challenges in treatment identification and dis- It is important to emphasize that many of these closure as we entered the new millennium.
    [Show full text]
  • Glossary of Geological Terms
    GLOSSARY OF GEOLOGICAL TERMS These terms relate to prospecting and exploration, to the regional geology of Newfoundland and Labrador, and to some of the geological environments and mineral occurrences preserved in the province. Some common rocks, textures and structural terms are also defined. You may come across some of these terms when reading company assessment files, government reports or papers from journals. Underlined words in definitions are explained elsewhere in the glossary. New material will be added as needed - check back often. - A - A-HORIZON SOIL: the uppermost layer of soil also referred to as topsoil. This is the layer of mineral soil with the most organic matter accumulation and soil life. This layer is not usually selected in soil surveys. ADIT: an opening that is driven horizontally (into the side of a mountain or hill) to access a mineral deposit. AIRBORNE SURVEY: a geophysical survey done from the air by systematically crossing an area or mineral property using aircraft outfitted with a variety of sensitive instruments designed to measure variations in the earth=s magnetic, gravitational, electro-magnetic fields, and/or the radiation (Radiometric Surveys) emitted by rocks at or near the surface. These surveys detect anomalies. AIRBORNE MAGNETIC (or AEROMAG) SURVEYS: regional or local magnetic surveys that measures deviations in the earth=s magnetic field and carried out by flying a magnetometer along flight lines on a pre-determined grid pattern. The lower the aircraft and the closer the flight lines, the more sensitive is the survey and the more detail in the resultant maps. Aeromag maps produced from these surveys are important exploration tools and have played a major role in many major discoveries (e.g., the Olympic Dam deposit in Australia).
    [Show full text]