 | | Journal (issue) | | Minas Gérais, Brazil. See 'The location, geology and mineralogy of gem tourmalines in Brazil' on pp. 263-98...location, geology and mineralogy of gem tourmalines in Brazil Jacques P. Cassedanne, Dr. Sc. *, and Maurice Roditi...inner parts of the pegmatites, on each side of a quartz core or concentrated in pockets, which are variable...variably perthitized, albite, muscovite and milky quartz with some lepidolite, schorl and locally huge tabular...deposits of tourmaline include the Brumado mine (Bahia) which produces fine red uvite crystals and the |  | | Journal (issue) | | Napoleon Necklace (NMNH Gem #5019) on a background of quartz crystals. (Photograph by Lee Boltin, Smithsonian...1024-1025. NOTES ON INCLUSIONS IN TANZANITE AND TOURMALINATED QUARTZ By PETE J. DUNN, M.A., F.G.A. D e p a r...U A R T Z Tourmalinated (schorl) quartz from Governador Valadares, Minas Gérais, Brazil, is frequently...cabochon-cut or faceted gems. Gems of clear, colourless, quartz with the black needles of tourmaline are quite...unknown filamentary crystal in Brazilian tourmalinated quartz. (60 x ). FIG. 2. Graphite inclusions in |  | | Book | | ^^^Tmexicau Section I ENSENADA .n Felipe Section 11 Bahia de los Angeles GUERRERO NEGRO SANTA Section ...gold. You may be able to find some interesting quartz specimens in the mine dumps. Between 1969 and 1973...that clear crystals of brown clinozoisite occur in quartz veins near the scheelite mines up to four or five...unexplored by rockhounds, and, where there are jasper, quartz crystals (in the same area as the jasper), silver...Just after you pass the turnoff to the left for Bahia Santa Maria, the road begins to wind through some |  | | Book (edition) | | Data (CIP) (Information Sectorial Nucleus, SP, Brazil) I59 IBGM. Handbook of Gems / IBGM, DNPM. – 4...I. Title. CDU 549.091 Federative Republic of Brazil Ministry of Mines and Energy National Department...respect to the most commonly found and traded gems in Brazil. Such information is generally described in documents...to disclose our vast gemological assets both in Brazil and abroad. Therefore, this publication covers...Andradite Garnet 24 Apatite 25 Aquamarine 26 Aventurine Quartz 27 Bicolor Tourmaline 28 Bloodstone 29 Brazilianite |  | | Journal (issue) | | Articles The Jaguaragu pegmatite, Minas Gerais, Brazil ............................. 165 by J. P. Cassedanne...District in Peru, Indian M tn. (A L), C apelinha (Brazil) O r d e r F ro m : P o stag e $1 p e r c o p...Universitaria, Ilha do Fundao 21.190 Rio de Janeiro, Brazil Jeanete N. Alves Departamento de Recursos Minerais-RJ...Minerais-RJ Rua Marechal Deodoro 351 24.030 Niteroi, Brazil The Jaguaragupegmatite, discovered during World...of Belo Horizonte, in the state of Minas Gerais, Brazil. The >recise location is near the Jose M iranda |  | | Journal (issue) | | branch ‘pearl’ from a giant clam|Quartz beads imitating tourmalinated quartz p. 103 ARTICLES Feature Articles...Trace-element Composition of Paraíba-type Tourmaline from Brazil, Mozambique and Nigeria By Martin Okrusch, Andreas...cushion and ~5 ct stone in ring) and from Paraíba, Brazil (3.5 mm gems in bracelet and 4.02 ct oval). Courtesy...Leonardo Silva Souto (Gems in Gems, Teófilo Otoni, Brazil) had approximately 50 cabochons weighing up to...as the spectra of tantalite-(Mn) from north-east Brazil, which contained supplementary bands at 621, 547 |  | | Book (edition) | | stones best grades 2-2.5. OPAL: finest QUARTZ: QUARTZ: SPINEL: grades of precious 2-5; med. 1.25-2...durable is that they be as hard or harder than quartz. The table below shows the Mohs Scale of Hardness...Apatite of Hardness 6. Feldspar: moonstone, 7. Quartz: amethyst, citrine, etc. alabaster 8. Topaz...contain fine particles of quartz (hardness 7), and unless gems are harder than quartz, damage will result....well known. Thus, the transparent andalusite from Brazil, a handsome and durable gem, is readily salable |  | | Journal (issue) | | HELVITE AND TOURMALINE ACCOMPANIED BY GRUNERITE IN QUARTZ By E. J. GÜBELIN, Ph.D., C.G., F.G.A. Lucerne...helvite as an inclusion in tourmalinated quartz from Governador Valadares, Brazil, in the July 1975 issue...observed this same variety of mineral inclusion in quartz some 20 years ago. However, in those days we gemmologists...minerals in a rock crystal from Governador Valadares, Brazil, consists of yellow tetrahedra of helvite, dark...various fibrous or acicular filaments in the four quartz specimens investigated by the electron microprobe |  | | Book | | identified by their conchoidal fracture. cludes some quartz w hich has a hardness The rarity of gemstones...become scratched with time. exceptionally rare. Quartz is found world¬ The toughness of gemstones is...9 Corundum 4 Fluorite 6.5 Steel file 10 Quartz Diamond INTRODUCTION PROPERTIES OF GEMSTONES...Probably Diamonds have been imitated by many Brazil and most gems, although small, the most famous...ability of diamond to found in river gravels in Bahia, Brazil. of South Africa was found weighing 83.5 conduct |  | | Journal (issue) | | e from Madagascar|Lalique quartz pendant in polarized light|Faceted quartz with petroleum inclusions...inclusions from Pakistan|Quartz slabs from Inner Mongolia|Sphalerite inclusions in quartz|Ruby from Liberia|Unstable...variable composition ranging from dacite-trachyte to quartz diorite (Elyasi et al., 1977). The apatite is thought...The apatite-bearing pockets were associated with quartz, albite and muscovite. The initial finds consisted...and some were found on a matrix of transparent quartz crystals. In addition to purple, the apatite colours |  | | Journal (issue) | | Strontianlte Sillimanite Pyrolusite Cinnabar Magnesite Quartz Bruclte Woilastonlte Hausmannlte Garnierite Braunite...specimens only) .......... 70 Specimens Purpuri te Rose Quartz Petrified Wood Opal lepidollte (Yellow) Chalk Nephrite...Andradite Spessartine Opallzed Wood Thullte Rutilated Quartz Marlposlte ldocrase Grossular Dumortierite ¼" Aquamarine...Mlzzonite-Scapollte Bloodstone Tigereye Amber Smoky Quartz ¼" Peridot Axlnite limonite Pseudomorph Concretion...Pirssonlte - xi Phylllte Gastropod Rock Crystal Quartz - xi Coqulna • obsidian " apache tears" • Hexahydrlte |  | | Book | | example is very rare indeed compared to salt or quartz, but not compared to ruby, the particular conditions...of it crystallizes as free silica in the form of quartz, as in a granite. Along with the increasing silica...crystals (resembling bamboo stalks) in some emerald, quartz and garnet • anatase in rock crystal • apatite...fuchsite in quartz, emerald and corundum pyrite in corundum and emerald rutile in quartz spinel in ruby...diamond. Pegmatite minerals such as apatite and quartz may be found in another pegmatitic mineral, aquamarine |  | | Book (edition) | | discovered that a series of measure1nents 1nade on quartz crystals from different localities alvvays yielded...mentioned, also measured interfacial an gles of quartz with similar MINERALOGY 8 results, and he further...wulf enite. Hexag?nal System Hexagonal pris1ns, quartz, apatite, beryl; hexagonal pyramids, corundum,...Penetration _Tivins ~laurolite, fiuorite , quartz (Brazil and Dauphine), orthoclase. Contact Twins Calclle... INTRODUCTION 11 CRYSTALLINE AGGREGATES SUITE Druses Quartz (geode or cavity lining), calcite. G ranu lar Granite |  | | Book | | fibrous radiating structure. Opposite: gold on quartz from California. CONTENTS INTRODUCTION 7 THE...metamorphic rock, and in sea water. Auriferous quartz is a major source for gold and occurs in hydrothermal...Localities. Apart from South Africa, Above: Gold on quartz from California. Such a specimen would command...gold visible Left: Another fine example of gold on quartz, also from California gold is found in Rhodesia...iron stains may be removed by any convenient acid. Quartz may be removed by strong hydrofluoric acid. Left: |  | | Book (edition) | | objects all things considered, or Japanese twins of quartz which, to the beginner, may look little different...one because tvvo of its minerals, feldspar and quartz, are the most abundant of all minerals. This class...well-known polymorphs are tridymite, cristobalite, and quartz, all of which are silicon dioxide, and rutile,...such it has practically the same composition as quartz, yet it always occurs in formless masses which...porous and relatively lighter than an equal mass of quartz. It must therefore contain numerous minute pores | | | Book (edition) | | objects all things considered, or Japanese twins of quartz which, to the beginner, may look little different...one because two of its minerals, feldspar and quartz, are the most abundant of all minerals. ‘This...well-known polymorphs are tridymite, cristobalite, and quartz, all of which are silicon dioxide, and rutile...such it has practically the same composition as quartz, yet it always occurs in formless masses which...porous and relatively lighter than an equal mass of quartz. It must therefore contain numerous minute pores |  | | Journal (volume) | | De Agostini website at: UK: AUS: SA: NZ: Rose quartz RO Ruby RU www.deagostini.co.uk www.deagostini...surface . u, tD -·3 se uar Rose quartz is an uncommon form of quartz that is often used in necklaces...shapeless specimens. D espite its name, rose quartz can in fact range in colour from pink through to...structure of the mineral. This rose-coloured variety of quartz is regarded as too valuable to be put to any of...of a clock mechanism, for example. Instead, rose quartz is set aside to be made into beautiful carved ornaments |  | | Book | | cristobalite (found only in volcanic lavas), tridymite, quartz, coesite and stishovite (found only in the impact... CLASSIFICATION Right: Magnesite crystals growing on quartz, a framework silicate a great variety of physical...further cations and forms the common oxide mineral quartz, Si02, and its rarer polymorphs. In other framework...then worked out Top: X-ray diffraction pattern of quartz cell. However, such methods remain too slow to...in granite are relatively large and consist of quartz (grey, white, 25 THE CRYSTALLINE STATE or colourless) | | | Book | | stishovite lavas), (found tridymite, only quartz, in the coesite impact areas and of meteorites...melilite CLASSIFICATION Right: Magnesite | quartz, a } MINERALS. if the mineral low the latter...polymorphs. silicates, such as the cations and quartz, SiO», In other framework feldspars and zeolites...worked out Top: X-ray diffraction pattern of quartz cell. However, such methods remain too slow to...in granite are relatively large and consist of quartz (grey, white, 25 ATE NE CRYSTA HE Left: |  | | Book | | Gemstones Clear Quartz Crystal 143 Beginning Gemstones: The Root Chakra 169 Smoky dian, Quartz, Black Tourmaline...Tourmaline, Tourmaline Quartz, Obsi- Onyx, Jet, Hematite, Bloodstone, Red Garnet, Ruby, Red Jasper...Red/Orange Coral, Agate, Jacinth, Topaz, Citrine Quartz, Tiger Eye, Golden 195 Amber, Beryl, Malachite...Gemstones: The Heart and Throat Chakras 219 Rose Quartz, Rhodochrosite, Pink Tourmaline, Watermelon Tourmaline...Opal, Amethyst, Zircon, Diamond, Rutile Quartz, Clear Quartz Crystal 245 Appendix 1 The Uses of |  | | Journal (issue) | | alexandrite • Conichalcite in quartz chalcedony • Emerald in rock crystal quartz • Iolite-sunstone intergrowth...spiral growth • Quarterly Crystal: “Ball bearing” in quartz 434 Gem News International Blue gahnite from...Opal Pearl Peridot Quartz Ruby Sapphire Spinel Topaz Turquoise Potosí Salvador da Bahia Rio de Janeiro...Coral, red Moonga Indian Ocean Boloor Crystal quartz Billoor Hyderabad, India Almas Diamond Hira...to this day. Rubies, sapphire, and rock crystal quartz were shipped in from Ceylon (Sri Lanka) and Pegu |  | | Book (edition) | | River, Va.; AMETHYST—F our Peaks, Arizona; Rose Quartz—Brazil. CaLIFORNITE—Siskiyou County, Calif.; Apatire...Texas; OPALIZED AQUAMARINE, Woop—State pendant—Brazil. Fourth Row Two Brazilian CrrrinEs, faceted....Garnet Group Jadeite Nephrite Olivine (peridot) Quartz (amethyst, citrine, chalcedony, etc.) Topaz Tourmaline...and in the gleaming coppery needles of rutilated quartz. Since gems are meant to be worn, they are liable...Top. Clear colorless quartz (rock crystal) from Arkansas. Bottom. Amethyst quartz from Pennsylvania. |  | | Book (volume) | | variety and wealth of locality information concerning quartz gemstones are recognized in a separate chapter...Rhodonite, Idocrase (Vesuvianite), The Garnet Group. Quartz FAMILY GEMSTONES RarRE AND UnusuaL GEMSTONES Chrysoberyl...DECORATIVE GEMSTONES Granite, Graphic Granite, Unakite, Quartz Porphyry (Leopardite), Orbicular Gabbro-Diorite...Asteriated rose quartz sphere Rough and faceted rose quartz Tourmalinated quartz Catseye quartz, binghamite...Turritella specimen Polished agate slices Quartz crystal Quartz sceptre crystal Three specimens of petrified |  | | Journal (issue) | | Strontianlte Sillimanlte Pyrolusite Cinnabar Magnesite Quartz Brucite Wol lastonlte Hausmannite Garnlerlte Braunlte...specimens only) .......... 70 Specimens Purpurite Rose Quartz Petrified Wood Opal Lepldollte (Yellow) Chalk Nephrite...lte Spessartine Opallzed Wood Thullte Rutllated Quartz Marlposlte ldocrase Grossular Oumortlerlte 1 Aquamarine...Mlzzonite-Scapolite Bloodstone Tigereye ¼" Amber Smoky Quartz 1/, " Peridot Axlnite Llmonlte Pseudomorph Concretion...xi Phylllte Hexahydrlte Gastropod Rock Crystal Quartz - xi Coquina •obsidian "apache tears" (Epsomlte) |  | | Journal (issue) | | Cuts FORMS and SHAPES in any slabbed stone - Jade. quartz. agate, glass. etc. Works well on Metalics such... By Lyle D. Hardy INSTRUCTIONS Angles are for quartz. Index settings are for a 64 index gear. Consider:tble...second specimen from the left Is from Minas Gerals, Brazil; the others are from San Diego County, California...colored tourmalines from various localities in Brazil. Obviously the term is misleading and totally inaccurate...that very choice natural emeralds are found in Brazil. The term, "Brazilian sapphire," has also been |
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