A Tale of Two Garnets: the Role of Solid Solution in the Development Toward a Modern Mineralogyk
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How to Identify Rocks and Minerals
How to Identify Rocks and Minerals fluorite calcite epidote quartz gypsum pyrite copper fluorite galena By Jan C. Rasmussen (Revised from a booklet by Susan Celestian) 2012 Donations for reproduction from: Freeport McMoRan Copper & Gold Foundation Friends of the Arizona Mining & Mineral Museum Wickenburg Gem & Mineral Society www.janrasmussen.com ii NUMERICAL LIST OF ROCKS & MINERALS IN KIT See final pages of book for color photographs of rocks and minerals. MINERALS: IGNEOUS ROCKS: 1 Talc 2 Gypsum 50 Apache Tear 3 Calcite 51 Basalt 4 Fluorite 52 Pumice 5 Apatite* 53 Perlite 6 Orthoclase (feldspar group) 54 Obsidian 7 Quartz 55 Tuff 8 Topaz* 56 Rhyolite 9 Corundum* 57 Granite 10 Diamond* 11 Chrysocolla (blue) 12 Azurite (dark blue) METAMORPHIC ROCKS: 13 Quartz, var. chalcedony 14 Chalcopyrite (brassy) 60 Quartzite* 15 Barite 61 Schist 16 Galena (metallic) 62 Marble 17 Hematite 63 Slate* 18 Garnet 64 Gneiss 19 Magnetite 65 Metaconglomerate* 20 Serpentine 66 Phyllite 21 Malachite (green) (20) (Serpentinite)* 22 Muscovite (mica group) 23 Bornite (peacock tarnish) 24 Halite (table salt) SEDIMENTARY ROCKS: 25 Cuprite 26 Limonite (Goethite) 70 Sandstone 27 Pyrite (brassy) 71 Limestone 28 Peridot 72 Travertine (onyx) 29 Gold* 73 Conglomerate 30 Copper (refined) 74 Breccia 31 Glauberite pseudomorph 75 Shale 32 Sulfur 76 Silicified Wood 33 Quartz, var. rose (Quartz, var. chert) 34 Quartz, var. amethyst 77 Coal 35 Hornblende* 78 Diatomite 36 Tourmaline* 37 Graphite* 38 Sphalerite* *= not generally in kits. Minerals numbered 39 Biotite* 8-10, 25, 29, 35-40 are listed for information 40 Dolomite* only. www.janrasmussen.com iii ALPHABETICAL LIST OF ROCKS & MINERALS IN KIT See final pages of book for color photographs of rocks and minerals. -
Structure and Physical Properties of Hydrogrossular Mineral Series
STRUCTURE AND PHYSICAL PROPERTIES OF HYDROGROSSULAR MINERAL SERIES A THESIS IN PHYSICS Presented to the Faculty of the University of Missouri-Kansas City in Partial requirements for the degree MASTER OF SCIENCE By PUJA ADHIKARI M.Sc, Tribhuban University, Kathmandu, Nepal, 2010 Kansas City, Missouri 2015 ©2015 PUJA ADHIKARI ALL RIGHTS RESERVED Structure and physical properties of Hydrogrossular mineral series Puja Adhikari, Candidate for the Master of Science Degree University of Missouri-Kansas City, 2015 ABSTRACT The mineral hydrogrossular series (Ca3Al2(SiO4)3-x(OH) 4x; 0 ≤ x ≤ 3) are important water bearing minerals found in the upper and lower part of the Earth’s mantle. They are vital to the planet’s hydrosphere under different hydrothermal conditions. The composition and structure of this mineral series are important in geoscience and share many commonalities with cement and clay materials. Other than the end members of the series x = 0 (grossular) and x = 3 (katoite) which have a cubic garnet structure, the structure of the series is totally unknown. We used large-scale ab initio modeling to investigate the structures and properties for hydrogrossular series for x = 0, 0.5, 1, 1.5, 2, 2.5, 3. Results indicate that for x > 0 and x < 3, the structures are tetragonal. This shows that there is structural change related to the lowering of overall symmetry associated with the composition of SiO4 tetrahedra and AlO6 octahedra. Total Bond order also explains the reason behind the change in the compressibility of the series. The electronic structure, mechanical and optical properties of the hydrogrossular series are calculated and the results for grossular and katoite are in good agreement with the available experimental data. -
Download PDF About Minerals Sorted by Mineral Name
MINERALS SORTED BY NAME Here is an alphabetical list of minerals discussed on this site. More information on and photographs of these minerals in Kentucky is available in the book “Rocks and Minerals of Kentucky” (Anderson, 1994). APATITE Crystal system: hexagonal. Fracture: conchoidal. Color: red, brown, white. Hardness: 5.0. Luster: opaque or semitransparent. Specific gravity: 3.1. Apatite, also called cellophane, occurs in peridotites in eastern and western Kentucky. A microcrystalline variety of collophane found in northern Woodford County is dark reddish brown, porous, and occurs in phosphatic beds, lenses, and nodules in the Tanglewood Member of the Lexington Limestone. Some fossils in the Tanglewood Member are coated with phosphate. Beds are generally very thin, but occasionally several feet thick. The Woodford County phosphate beds were mined during the early 1900s near Wallace, Ky. BARITE Crystal system: orthorhombic. Cleavage: often in groups of platy or tabular crystals. Color: usually white, but may be light shades of blue, brown, yellow, or red. Hardness: 3.0 to 3.5. Streak: white. Luster: vitreous to pearly. Specific gravity: 4.5. Tenacity: brittle. Uses: in heavy muds in oil-well drilling, to increase brilliance in the glass-making industry, as filler for paper, cosmetics, textiles, linoleum, rubber goods, paints. Barite generally occurs in a white massive variety (often appearing earthy when weathered), although some clear to bluish, bladed barite crystals have been observed in several vein deposits in central Kentucky, and commonly occurs as a solid solution series with celestite where barium and strontium can substitute for each other. Various nodular zones have been observed in Silurian–Devonian rocks in east-central Kentucky. -
A Ground Magnetic Survey of Kimberlite Intrusives in Elliott County, Kentucky
Kentucky Geological Survey James C. Cobb, State Geologist and Director University of Kentucky, Lexington A Ground Magnetic Survey of Kimberlite Intrusives in Elliott County, Kentucky John D. Calandra Thesis Series 2 Series XII, 2000 Kentucky Geological Survey James C. Cobb, State Geologist and Director University of Kentucky, Lexington A Ground Magnetic Survey of Kimberlite Intrusives in Elliott County, Kentucky John D. Calandra On the cover: Photomicrographs of olivine phenoc- rysts: (top) a stressed first-generation olivine pheno- cryst and (bottom) a late-stage olivine phenocryst. Thesis Series 2 Series XII, 2000 i UNIVERSITY OF KENTUCKY Computer and Laboratory Services Section: Charles T. Wethington Jr., President Steven Cordiviola, Head Fitzgerald Bramwell, Vice President for Research and Richard E. Sergeant, Geologist IV Graduate Studies Joseph B. Dixon, Information Technology Manager I Jack Supplee, Director, Administrative Affairs, Research James M. McElhone, Information Systems Technical and Graduate Studies Support Specialist IV Henry E. Francis, Scientist II KENTUCKY GEOLOGICAL SURVEY ADVISORY Karen Cisler, Scientist I BOARD Jason S. Backus, Research Analyst Henry M. Morgan, Chair, Utica Steven R. Mock, Research Analyst Ron D. Gilkerson, Vice Chair, Lexington Tracy Sizemore, Research Analyst William W. Bowdy, Fort Thomas Steve Cawood, Frankfort GEOLOGICAL DIVISION Hugh B. Gabbard, Winchester Coal and Minerals Section: Kenneth Gibson, Madisonville Donald R. Chesnut Jr., Head Mark E. Gormley, Versailles Garland R. Dever Jr., Geologist V Rosanne Kruzich, Louisville Cortland F. Eble, Geologist V W.A. Mossbarger, Lexington Gerald A. Weisenfluh, Geologist V Jacqueline Swigart, Louisville David A. Williams, Geologist V, Henderson office John F. Tate, Bonnyman Stephen F. Greb, Geologist IV David A. -
Coulsonite Fev2o4—A Rare Vanadium Spinel Group Mineral in Metamorphosed Massive Sulfide Ores of the Kola Region, Russia
minerals Article Coulsonite FeV2O4—A Rare Vanadium Spinel Group Mineral in Metamorphosed Massive Sulfide Ores of the Kola Region, Russia Alena A. Kompanchenko Geological Institute of the Federal Research Centre “Kola Science Centre of the Russian Academy of Sciences”, 14 Fersman Street, 184209 Apatity, Russia; [email protected]; Tel.: +7-921-048-8782 Received: 24 August 2020; Accepted: 21 September 2020; Published: 24 September 2020 Abstract: This work presents new data on a rare vanadium spinel group mineral, i.e., coulsonite FeV2O4 established in massive sulfide ores of the Bragino occurrence in the Kola region, Russia. Coulsonite in massive sulfide ores of the Bragino occurrence is one of the most common vanadium minerals. Three varieties of coulsonite were established based on its chemical composition, some physical properties, and mineral association: coulsonite-I, coulsonite-II, and coulsonite-III. Coulsonite-I forms octahedral crystal clusters of up to 500 µm, and has a uniformly high content of 2 Cr2O3 (20–30 wt.%), ZnO (up to 4.5 wt.%), and MnO (2.8 wt.%), high microhardness (743 kg/mm ) and coefficient of reflection. Coulsonite-II was found in relics of quartz–albite veins in association with other vanadium minerals. Its features are a thin tabular shape and enrichment in TiO2 of up to 18 wt.%. Coulsonite-III is the most common variety in massive sulfide ores of the Bragino occurrence. Coulsonite-III forms octahedral crystals of up to 150 µm, crystal clusters, and intergrowths with V-bearing ilmenite, W-V-bearing rutile, Sc-V-bearing senaite, etc. Chemical composition of coulsonite-III is characterized by wide variation of the major compounds—Fe, V, Cr. -
Geology Club Mineral: Collecting Trip
Geology Club: Mineral Collecting Trip (10 October 2009) Trip Notes by Charles Merguerian STOP 1 – Grossular Garnet Locality, West Redding, Connecticut. [UTM Coordinates: 630.71E / 4575.38N, Bethel quadrangle]. Covering roughly 60 acres of land, this enigmatic massive fine-grained grossularite garnet + diopside rock in West Redding has made many mineral collectors and geologists take notice. Walk up the steep slope east of Simpaug Turnpike to see highly fractured, massive cinnamon-colored grossular garnet rock, part of a 0.6-km wide heart-shaped mass found at the faulted contact between the Stockbridge Marble (OCs) and injected muscovitic schist of the Rowe Schist member (OCr) of the Hartland Formation (Figure 1). According to Rodgers et al. (1985), we are very near Cameron’s Line (red and black line in Figure 1). Figure 1 – Geologic map of the area surrounding Stop 1 showing the Proterozoic gneissic rocks (Yg) and Cambrian Dalton Schist (Cd) to the west, the Stockbridge Marble (OCs), Cameron’s Line (CL in red), the injected schistose rocks of the Rowe Formation (OCr), and an Ordovician granitoid (Og) that may be responsible for this unusual Ca++-enriched skarn deposit. Note the NW-trending high-angle brittle faults that cut the region. (Adapted from Rodgers et al. 1985.) Two knolls at this locality are almost entirely composed of grossularite garnet (var. essonite) and lesser clinopyroxene. Mostly the garnet occurs alone with minor quartz and localized quartz veining has been observed. Chemical analysis of the garnet (SiO2 = 39.10%, CaO = 34.85%, Al2O3 = 19.61%, and total FeO+Fe2O3 = 5.44%), are quite similar to published analyses of grossular garnet, including the phenomenal grossular garnet crystals from Morelos, Mexico. -
ECONOMIC GEOLOGY RESEARCH INSTITUTE HUGH ALLSOPP LABORATORY University of the Witwatersrand Johannesburg
ECONOMIC GEOLOGY RESEARCH INSTITUTE HUGH ALLSOPP LABORATORY University of the Witwatersrand Johannesburg CHROMITITES OF THE BUSHVELD COMPLEX- PROCESS OF FORMATION AND PGE ENRICHMENT J.A. KINNAIRD, F.J. KRUGER, P.A.M. NEX and R.G. CAWTHORN INFORMATION CIRCULAR No. 369 UNIVERSITY OF THE WITWATERSRAND JOHANNESBURG CHROMITITES OF THE BUSHVELD COMPLEX – PROCESSES OF FORMATION AND PGE ENRICHMENT by J. A. KINNAIRD, F. J. KRUGER, P.A. M. NEX AND R.G. CAWTHORN (Department of Geology, School of Geosciences, University of the Witwatersrand, Private Bag 3, P.O. WITS 2050, Johannesburg, South Africa) ECONOMIC GEOLOGY RESEARCH INSTITUTE INFORMATION CIRCULAR No. 369 December, 2002 CHROMITITES OF THE BUSHVELD COMPLEX – PROCESSES OF FORMATION AND PGE ENRICHMENT ABSTRACT The mafic layered suite of the 2.05 Ga old Bushveld Complex hosts a number of substantial PGE-bearing chromitite layers, including the UG2, within the Critical Zone, together with thin chromitite stringers of the platinum-bearing Merensky Reef. Until 1982, only the Merensky Reef was mined for platinum although it has long been known that chromitites also host platinum group minerals. Three groups of chromitites occur: a Lower Group of up to seven major layers hosted in feldspathic pyroxenite; a Middle Group with four layers hosted by feldspathic pyroxenite or norite; and an Upper Group usually of two chromitite packages, hosted in pyroxenite, norite or anorthosite. There is a systematic chemical variation from bottom to top chromitite layers, in terms of Cr : Fe ratios and the abundance and proportion of PGE’s. Although all the chromitites are enriched in PGE’s relative to the host rocks, the Upper Group 2 layer (UG2) shows the highest concentration. -
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 .................................... -
Fluorian Garnets from the Host Rocks of the Skaergaard Intrusion: Implications for Metamorphic Fluid Composition
American Mineralogist, Volume 75, pages 859-873,1990 Fluorian garnets from the host rocks of the Skaergaard intrusion: Implications for metamorphic fluid composition CRAIG E. MANNING, * DENNIS K. BIRD Department of Geology, Stanford University, Stanford, California 94305, U.S.A. ABSTRACT Zoned, silica-deficient, calcic garnets containing up to 5 mol% F substitution for 0 formed during contact metamorphism of basalts by the Skaergaard intrusion in East Greenland. Fluorian calcic garnets occur as a retrograde alteration of prograde wollastonite and clinopyroxene that fills vesicles and vugs in lavas 30-70 m from the intrusion. Para- genetically equivalent phases include fluorite, wollastonite, calcic clinopyroxene, prehnite, quartz, and calcite. Electron microprobe analysis shows that the garnets are :::-:93mol% grossular-andradite (grandite) solid solutions and that the F content does not fully com- pensate for the silica deficiency, suggesting the presence of a hydrous component in the garnets. The garnets display discontinuous zoning with respect to Al and Fe, and increases in F, calculated OH, and the Si deficiency with increasing Al concentration are observed. The garnets formed at temperatures between 200 and 420°C based on the coexisting mineral assemblage, and stratigraphic reconstructions indicate pressures of ~ 1 kbar. Assessment of isobaric, isothermal phase relations in the system CaO-A1203-Si02-H20- HF allows estimation of fluid characteristics in equilibrium with fluorian grandite-bearing assemblages. The presence of fluorite, wollastonite, quartz, and calcite with these garnets combined with fluid inclusion data require that the activity (a) of H20 was ~ 1 and that aH.aF was 10-105 to 10-10.0in the coexisting hydrothermal solutions at 200-420 °C and 1 kbar. -
The Effect of Reduced Activity of Anorthite on the Reaction Grossular
AmericanMineralogist, Volume61, pages 889-896,1976 The effectof reducedactivity of anorthiteon thereaction grossular * quartz : anorthite* wollastonite:a modelfor plagioclasein the earth'slower crust anh upper mantle K. E. WrNnoMr AND A. L. BoerrcHrnl Department of Geosciences,The Pennsyluania State (lniuersity Uniuersity Park, Pennsyluania 16802 Abstract The reaction CasAlrSiaor, + SiO, : CaAlzSiros + 2 CaSiOg (erossular) (quartz) (anortbite) (wollastoDite) wasinvestigated at l10ooC,using intermediate-composition plagioclase to determinethe shift of the equilibriumpressure as a functionof compositionat pressureand temperaturecondi- tions representativeof the earth'slower crustand uppermantle. For compositionswithin the rangeAnro-,00, activity of the anorthitecomponent is equalto its molefraction. For composi- tions more albitic than about Anro,the activity of the anorthitecomponent equals its mole fractionmultiplied by a constantfactor of 1.2.This latter behavioris interpretedas a resultof anorthite-likedomains being in an energeticallyunfavorable environment for thesecomposi- tions. Applicationof the data obtainedfrom subsolidusexperiments to meltingbehavior indicates that plagioclaseliquids do not obey Raoult'sLaw, but havean activitycoefficient similar to crystallineplagioclase. This hypothesisis supportedby high-pressuremelting experiments for both anhydrousand hydroussystems. In parts of the lower crustcomposed of basicrock (e.g.gabbro), the calcicplagioclase will be consumedat relativelyshallow levels and over a narrow (2-3 km) -
Contribution to the Mineralogy of Norway, No
Contribution to the mineralogy of Norway, No. 58 NORWE GIAN CHROM IAN UGRAND ITE-GAR NETS TORE PRESTVIK Prestvik, T.: Norwegian chromian ugrandite-garnets. Contribution to the miner alogy of Norway, No. 58. Norsk Geologisk Tidsskrift, Vol. 54, pp. 177-182. Oslo 1974. Chromian garnets from the Røros district and from the Oslo Region have been analysed chemically and were found to contain 61 and 44 % of the uvarovite molecule respectively. A new occurrence of chromian grossular is described from inclusions of the monzodiorite rocks in the Velfjorden area, Nordland. T. Prestvik, Geologisk institutt, Universitetet i Trondheim, 7034 Trondheim - NTH, Norway. Chromian garnets of the pyralspite solid-solution series occur in rocks which crystallized at high pressure. Such garnets have been described fr om peridotite in the Møre district (Hysingjord 1967, Carswell 1968). Uvarovite has been fo und only in two localities in Norway (Neumann 1959). The uvarovite fr om Rødtjern mine in the ultramafic rocks of Feragen of the Røros district has been known for a relatively long time, and good samples were found in the collections at both Mineralogisk-geologisk museum at Universitetet i Oslo and at Geologisk institutt at Universitetet i Trondheim. The uvarovite fr om Rødtjern has previously been analysed (Aars-Andersen 1907) and was then fo und to have a very high chromium content. Uvarovite from this locality has also been reported by Falck-Muus sen. (1957). The uvarovite from Kalkovnen, Grua in the Oslo Region, has not yet been described. The only sample known from this locality occurs in the collections of Mineralogisk-geologisk museum in Oslo. -
The World of Pink Diamonds and Identifying Them
GEMOLOGY GEMOLOGY as to what dealers can do to spot them using standard, geologists from Ashton Joint Venture found certain indicator The World of Pink Diamonds inexpensive instruments. The commercial signifcance of minerals (such as ilmenite, chromite, chrome diopside, the various types will also be touched on. and pyrope garnet) in stream-gravel concentrates which indicated the presence of diamond-bearing host rocks. and Identifying Them Impact of Auction Sales Lamproites are special ultrapotassic magnesium-rich In the late 1980s, the public perception surrounding fancy- mantle-derived volcanic rocks with low CaO, Al2O3, Na2O colored diamonds began to change when the 0.95-carat and high K2O. Leucite, glass, K-richterite, K-feldspar and Cr- By Branko Deljanin, Dr Adolf Peretti, ‘Hancock Red’ from Brazil was sold for almost $1 million per spinel are unique to lamproites and are not associated with and Matthias Alessandri carat at a Christie’s auction. This stone was studied by one kimberlites. The diamonds in lamproites are considered to be of the authors (Dr. Adolf Peretti) at that time. Since then, xenocrysts and derived from parts of the lithospheric mantle Dr. Peretti has documented the extreme impact this one that lies above the regions of lamproite genesis. Kimberlites sale has had on subsequent prices and the corresponding are also magmatic rocks but have a different composition recognition of fancy diamonds as a desirable asset class. The and could contain non-Argyle origin pink diamonds. demand for rare colors increased and the media began to play a more active role in showcasing new and previously Impact of Mining Activities unknown such stones.