Pegmatite Deposits of Virginra
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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. -
The Anjahamiary Pegmatite, Fort Dauphin Area, Madagascar
The Anjahamiary pegmatite, Fort Dauphin area, Madagascar Federico Pezzotta* & Marc Jobin** * Museo Civico di Storia Naturale, Corso Venezia 55, I-20121 Milano, Italy. ** SOMEMA, BP 6018, Antananarivo 101, Madagascar. E-mail:<[email protected]> 21 February, 2003 INTRODUCTION Madagascar is among the most important areas in the world for the production, mainly in the past, of tourmaline (elbaite and liddicoatite) gemstones and mineral specimens. A large literature database documents the presence of a number of pegmatites rich in elbaite and liddicoatite. The pegmatites are mainly concentrated in central Madagascar, in a region including, from north to south, the areas of Tsiroanomandidy, Itasy, Antsirabe-Betafo, Ambositra, Ambatofinandrahana, Mandosonoro, Ikalamavony, Fenoarivo and Fianarantsoa (e.g. Pezzotta, 2001). In general, outside this large area, elbaite-liddicoatite-bearing pegmatites are rare and only minor discoveries have been made in the past. Nevertheless, some recent work made by the Malagasy company SOMEMEA, discovered a great potential for elbaite-liddicoatite gemstones and mineral specimens in a large, unusual pegmatite (the Anjahamiary pegmatite), hosted in high- metamorphic terrains. The Anjahamiary pegmatite lies in the Fort Dauphin (Tôlanaro) area, close to the southern coast of Madagascar. This paper reports a general description of this locality, and some preliminary results of the analytical studies of the accessory minerals collected at the mine. Among the most important analytical results is the presence of gemmy blue liddicoatite crystals with a very high Ca content, indicating the presence in this tourmaline crystal of composition near the liddicoatite end-member. LOCATION AND ACCESS The Anjahamiary pegmatite is located about 70 km NW of the town of Fort Dauphin (Tôlanaro) (Fig. -
The I\,Iagnetic Separation of Soi'ie Alluvial I,Iinerals in I'ialaya*
THE AMERICAN MINERAI,OGIST, VOL. 41, JULY AUGUST, 1959 THE I\,IAGNETIC SEPARATION OF SOI'IE ALLUVIAL I,IINERALS IN I'IALAYA* B. H. FnNrant, Minerals Eramination Diaision, GeologicalSurttey D epartment, F'ederotion of M al,aya. Assrnlcr This paper presents the results of a seriesof magnetic separationswhich have been in- vestigated {or a number of minerals occurring in X{alayan alluvial concentrates.The pur- pose of the investigations was to establish,by the isolation of individual mineral species,a reproducible and reliable method for the identification and quantitative estimation of minerals in alluvial concentrates examined by the Geological Survey in Malaya In par- ticular was sought the isolation of columbite from ubiquitous ilmenite. All the separations were made on the small, highly sensitive Frantz Isodynamic Model L-1 laboratory separa- tor, The minerals which have been successfully separated include ailanite, anatase, andalu- site (and chiastolite), arsenopyrite, brookite, cassiterite,columbite, epidote, gahnite, garnet (pink), ilmenite, manganeseoxide (51.6/e Mn), monazite, pyrite, rutile, scheelite,siderite, staurolite, thorite, topaz, tourmaline, uranoan monazite, wolframite, xenotime, and zircon. PnocBpunp When using an inclined feed, the Frantz Isodynamic separator (see Figs. 1(A) & (B)) hasthree inherent variables. These are the field strengLh (current used),the sideslope, and the forward slope. 5;6s $lope wdrd 511)Pe (A) (B) Irc. 1. Diagrammatic representation of side slope and forward slope. The field strength is increasedby means of a rheostat which raises the current from zero in stagesof 0.05 amps. to 1.4 amps. Early in the investigationsit was decidedthat stepsof 0.1 amp. would be sufficiently gradual. -
The New IMA List of Gem Materials – a Work in Progress – Updated: July 2018
The New IMA List of Gem Materials – A Work in Progress – Updated: July 2018 In the following pages of this document a comprehensive list of gem materials is presented. The list is distributed (for terms and conditions see below) via the web site of the Commission on Gem Materials of the International Mineralogical Association. The list will be updated on a regular basis. Mineral names and formulae are from the IMA List of Minerals: http://nrmima.nrm.se//IMA_Master_List_%282016-07%29.pdf. Where there is a discrepancy the IMA List of Minerals will take precedence. Explanation of column headings: IMA status: A = approved (it applies to minerals approved after the establishment of the IMA in 1958); G = grandfathered (it applies to minerals discovered before the birth of IMA, and generally considered as valid species); Rd = redefined (it applies to existing minerals which were redefined during the IMA era); Rn = renamed (it applies to existing minerals which were renamed during the IMA era); Q = questionable (it applies to poorly characterized minerals, whose validity could be doubtful). Gem material name: minerals are normal text; non-minerals are bold; rocks are all caps; organics and glasses are italicized. Caveat (IMPORTANT): inevitably there will be mistakes in a list of this type. We will be grateful to all those who will point out errors of any kind, including typos. Please email your corrections to [email protected]. Acknowledgments: The following persons, listed in alphabetic order, gave their contribution to the building and the update of the IMA List of Minerals: Vladimir Bermanec, Emmanuel Fritsch, Lee A. -
Module 7 Igneous Rocks IGNEOUS ROCKS
Module 7 Igneous Rocks IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material ▪ Molten rock material below Earth’s surface is called magma ▪ Molten rock material erupted above Earth’s surface is called lava ▪ The name changes because the composition of the molten material changes as it is erupted due to escape of volatile gases Rocks Cycle Consolidation Crystallization Rock Forming Minerals 1200ºC Olivine High Ca-rich Pyroxene Ca-Na-rich Amphibole Intermediate Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar of liquid increases liquid of 2 Temperature decreases Temperature SiO Low K-feldspar Muscovite Quartz 700ºC BOWEN’S REACTION SERIES Rock Forming Minerals Olivine Ca-rich Pyroxene Ca-Na-rich Amphibole Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar K-feldspar Muscovite Quartz BOWEN’S REACTION SERIES Rock Forming Minerals High Temperature Mineral Suite Olivine • Isolated Tetrahedra Structure • Iron, magnesium, silicon, oxygen • Bowen’s Discontinuous Series Augite • Single Chain Structure (Pyroxene) • Iron, magnesium, calcium, silicon, aluminium, oxygen • Bowen’s Discontinuos Series Calcium Feldspar • Framework Silicate Structure (Plagioclase) • Calcium, silicon, aluminium, oxygen • Bowen’s Continuous Series Rock Forming Minerals Intermediate Temperature Mineral Suite Hornblende • Double Chain Structure (Amphibole) -
Maine the Way Life Should Be. Mineral Collecting
MAINE The Way Life Should Be. Mineral Collecting The Maine Publicity Bureau, Inc. Quarries You May Visit # 1 Topsham: The Fisher Quarry is located off Route 24 in Topsham. This locale is best known for crystals of topaz, green microlite, and dark blue tourmaline. It has also produced other minerals such as beryl, uraninite and cassiterite. #2 Machiasport: At an area known as Jasper Beach there is an abundance of vari-colored jasper and/or rhyolite specimens. Located on Route 92. #3 Buckfield: The Bennett Quarry, located between Buckfield and Paris Hill, has produced fine specimens of blue and pink beryl including some gem material. It is also known for crystals of quartz, green tourmaline and rare minerals. #4 Casco: The Chute Prospect is best known for vesuvianite. It is located east of Route 302-35. Crystals of “cinnamon” garnet, quartz and pyrite are also found here. #5 Georgetown: The Consolidated Feldspar Quarry has produced excel lent specimens of gem citrine quartz, tourmaline and spodumene. Rose Quartz, cookeite and garnet are also found. #6 Paris: Mount Mica is world famous for tourmaline and this gem material was discovered here in 1821. This is one of the most likely places for a collector to find tourmaline. Mount Mica has produced a host of other minerals including beryl, cookeite, black tourmaline, colum- bite, lepidolite and garnet. (Currently being mined) #7 Greenwood: The Tamminen Quarry and the Harvard Quarry, both located near Route 219, have produced an interesting variety of miner als. The Tamminen Quarry is best known for pseudo-cubic quartz crystals, montmorillonite, spodumene and garnet. -
Minerals of the San Luis Valley and Adjacent Areas of Colorado Charles F
New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/22 Minerals of the San Luis Valley and adjacent areas of Colorado Charles F. Bauer, 1971, pp. 231-234 in: San Luis Basin (Colorado), James, H. L.; [ed.], New Mexico Geological Society 22nd Annual Fall Field Conference Guidebook, 340 p. This is one of many related papers that were included in the 1971 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks. Copyright Information Publications of the New Mexico Geological Society, printed and electronic, are protected by the copyright laws of the United States. -
Geology, Geochemistry, and Mineral Resources of The
GEOLOGY, GEOCHEMISTRY, AND MINERAL RESOURCES OF THE UPPER CAURA RIVER AREA, BOLIVAR STATE, VENEZUELA by Gary B. Sidder1 and Felix Martinez2 Open-File Report 90-231 1990 This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards. Denver, Colorado 2CVG-TECMIN, Ciudad Bolivar, Venezuela TABLE OF CONTENTS 'age ABSTRACT..............................^ 1 INTRODUCTION......................... 2 REGIONAL GEOLOGY......................................................................................... 4 LOCAL GEOLOGY................................................................................................. 5 Description of Rock Units................................................................... 6 Structure................................................................................................... 8 GEOCHEMSTRY.............................................^ 9 Analytical Results................................................................................. 10 ECONOMC GEOLOGY................................. 21 REGIONAL CORRELATION.............................................................................. 22 SUMMARY AND CONCLUSIONS.................................................................... 23 ACKNOWLEDGMENTS..........................................................................^ 26 REFERENCES CITED............................................................................................ 27 LIST OF FIGURES AND TABLES Figure 1. Location map and geologic sketch -
INCLUSIONS in AQUAMARINE from AMBATOFOTSIKELY, MADAGASCAR Fabrice Danet, Marie Schoor, Jean-Claude Boulliard, Daniel R
NEW Danet G&G Fall 2012_Layout 1 9/27/12 11:31 AM Page 205 RAPID COMMUNICATIONS INCLUSIONS IN AQUAMARINE FROM AMBATOFOTSIKELY, MADAGASCAR Fabrice Danet, Marie Schoor, Jean-Claude Boulliard, Daniel R. Neuville, Olivier Beyssac, and Vincent Bourgoin grams of translucent to transparent beryl were pro- duced, as well as several tonnes of opaque material In January 2012, aquamarine crystals containing for industrial use. While only a very small percentage interesting inclusions were extracted from the Am- was suitable for faceting, several hundred aqua- batofotsikely area northwest of Antsirabe, Mada- marines in the 1–35 ct range have been cut. In April gascar. These specimens displayed various types 2012, one of the authors (FD) traveled to the locality of eye-visible and microscopic inclusions, and and obtained representative samples. some had an unusual form. Raman microspec- troscopy identified reddish brown plate lets as Location and Geologic Setting. The workings are lo- hematite, while ilmenite was found as black cated less than 1 km north of Ambatofotsikely (a village platelets, black needles, and distinctive dark gray now locally known as Ambatofotsy Carole), 22 km dendrites. Similar inclusions are known in beryl north-northwest of Ankazomiriotra, and 74 km north- from Brazil, India, Mozambique, and Sri Lanka. west of Antsirabe. The deposit is centered at coordinates 19°27.662¢S, 46°27.450¢E, at an elevation of 1,010 m. The site is accessed by a paved road (RN 34) from ining activity near the central Malagasy village Antsirabe to a point 16 km west of Ankazomiriotra. of Ambatofotsikely was first documented nearly From there, a trail extends 15 km to Ambatofotsikely. -
LAYERED PEGMATITE-APLITE Division of Earth Sciences, The
MINERALOGICAL SOCIETY OF AMERICA, SPECIAL PAPER 1, 1963 INTERNATIONALMINERALOGICALASSOCIATION,PAPERS, THIRD GENERAL MEETING LAYERED PEGMATITE-APLITE INTRUSIVES 1 RICHARD H. JAHNS AND O. FRANK TUTTLE Division of Earth Sciences, The Pennsylvania State University, University Park, Pennsylvania ABSTRACT Intrusive bodies of granitic pegmatite and aplite with simple or complex layering include those representing multiple injections of magma from external sources and those representing single injections of magma followed by segregation dur- ing crystallization. Those of the latter category can be subdivided into four classes, intergradations among which are not uncommon: 1. Bodies of aplite or fine-grained pegmatite with very large phenocrysts, or megacrysts. 2. Aplite bodies with mar- ginal or interior pegmatite masses generally formed in situ. 3. Pegmatite bodies with marginal or interior aplite masses formed in situ or by autoinjection. 4. Highly asymmetric bodies whose upper parts consist mainly or wholly of pegmatite and whose lower parts consist mainly or wholly of aplite. Zonal structure defines a gross layering within many pegmatite bodies, and a layer-like distribution of pegmatite and aplite also is common over a wide range of scales. Some of the aplites are faintly to distinctly flow layered, and others are featured by rhythmic layering in which adjacent thin and regular units differ from each other in composition. None of the observed types of layering is regarded as a result of crystal accumulation. The bulk composition of the layered intrusive bodies falls in the thermal valley of petrogeny's residua system at an average composition corresponding to a parent magma saturated with water at high pressures (e.g. -
(FP)-Rich Aplite-Pegmatites in the Central Iberian Zone Geologic
Ore Geology Reviews 95 (2018) 408–430 Contents lists available at ScienceDirect Ore Geology Reviews journal homepage: www.elsevier.com/locate/oregeorev Petrogenetic relationships between Variscan granitoids and Li-(F-P)-rich T aplite-pegmatites in the Central Iberian Zone: Geological and geochemical constraints and implications for other regions from the European Variscides ⁎ E. Roda-Roblesa, , C. Villasecab, A. Pesqueraa, P.P. Gil-Crespoa, R. Vieirac, A. Limac, I. Garate-Olavea a Dpto. Mineralogía y Petrología, Universidad del País Vasco UPV/EHU, Barrio Sarriena s/n, 48940 Leioa, Spain b Dpto. Petrología y Geoquímica, Universidad Complutense, IGEO (UCM, CSIC), 28040 Madrid, Spain c Instituto de Ciências da Terra, Universidade do Porto/DGAOT, Rua do Campo Alegre 687, 4169-007 Porto, Portugal ARTICLE INFO ABSTRACT Keywords: The Central Iberian Zone (CIZ) is characterised by a large volume of Variscan granitic intrusions, which can be Li-rich aplite-pegmatites grouped into five types: (1) two-mica peraluminous leucogranites (S1); (2) P-rich highly peraluminous granites Granite batholiths (S2); (3) P-poor moderately peraluminous granites (S3); (4) moderately to low peraluminous granites (S4); and Geochemistry (5) I-type low peraluminous granites (I). Though not as abundant as granites, aplite-pegmatite rocks are Central Iberian Zone nonetheless widespread in this region, occurring either as fields of aplite-pegmatite dykes or as leucogranitic European Variscan Belt cupolas. They are commonly enriched in Li-(F-P) minerals such as spodumene, petalite, micas, and phosphates of the amblygonite-montebrasite and triphylite-lithiophilite series. Many of the Li-rich bodies show an aplitic texture, frequently with the development of layered units. -
Mineralogy and Origin of the Titanium
MINERALOGY AND ORIGIN OF THE TITANIUM DEPOSIT AT PLUMA HIDALGO, OAXACA, MEXICO by EDWIN G. PAULSON S. B., Massachusetts Institute of Technology (1961) SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY May 18, 1962 Signature of At r . Depardnent of loggand Geophysics, May 18, 1962 Certified by Thesis Supervisor Ab Accepted by ...... Chairman, Departmental Committee on Graduate Students M Abstract Mineralogy and Origin of the Titanium Deposit at Pluma Hidalgo, Oaxaca, Mexico by Edwin G. Paulson "Submitted to the Department of Geology and Geophysics on May 18, 1962 in partial fulfillment of the requirements for the degree of Master of Science." The Pluma Hidalgo titanium deposits are located in the southern part of the State of Oaxaca, Mexico, in an area noted for its rugged terrain, dense vegetation and high rainfall. Little is known of the general and structural geology of the region. The country rocks in the area are a series of gneisses containing quartz, feldspar, and ferromagnesians as the dominant minerals. These gneisses bear some resemblance to granulites as described in the literature. Titanium minerals, ilmenite and rutile, occur as disseminated crystals in the country rock, which seems to grade into more massive and large replacement bodies, in places controlled by faulting and fracturing. Propylitization is the main type of alteration. The mineralogy of the area is considered in some detail. It is remarkably similar to that found at the Nelson County, Virginia, titanium deposits. The main minerals are oligoclase - andesine antiperthite, oligoclase- andesine, microcline, quartz, augite, amphibole, chlorite, sericite, clinozoi- site, ilmenite, rutile, and apatite.