 | | Book | | Professor Jacques P. Cassedanne Universidade Federal do Rio de Janeiro For his valuable participation in research...1982 Jules Roger Sauer ” Foreword For years Brazil has been the major producer of colored stones in...metamorphic rocks, the variety of gem deposits in Brazil is almost infinite. In addition to the mineral...assemblage one might expect from pegmatite dikes, Brazil also produces a very significant output of diamonds...written in English, and beautifully illustrated. “Brazil, Paradise of Gemstones’, by Jules Roger Sauer, |  | | Journal (issue) | | Articles 708 Coloured Stone Mining and Trade in Brazil: A Brief History and Current Status By Aurélien...Collection V. L. Villani photo p. 758 Cover Photo: Brazil is the source of a variety of coloured stones,...Gemmology, 35(8), 2017 Gem Notes a b c d cedony (agate), danburite, scapolite, moonstone and kornerupine...Saint-Clair Fonseca Junior (BC Gemas do Brasil, Governador Valadares, Brazil), and heating to 500°C in air was...recently had the pleasure to study two chalcedony/agate cameos that were fascinating for their gemmological |  | | Journal (article/letter/editorial) | | Review Mineralogy, Geochemistry and Genesis of Agate—A Review Jens Götze 1, *, Robert Möckel 2 and Yuanming...20 November 2020 Abstract: Agate—a spectacular form of SiO2 and a famous gemstone—is...interstitial molecular H2 O and silanol groups. Most agate occurrences worldwide are related to SiO2 -rich...rocks. It is assumed that the supply of silica for agate formation is often associated with late- or post-volcanic...studies point to a range between 20 and 230 ◦ C for agate formation temperatures. The accumulation and condensation |  | | Book | | BARTORELLI ::• . . .. MINERALS & PRECIOUS STONES OF BRAZIL Sponsored by: VALE MINISTER.IO DA CULTURA ©...Crystal of multicolored tourmaline (84 x 26 mm), Lavra do Sapo, Ferruginha, Conselheiro Pena, Minas Gerais...(Camara Brasileira do Livro, SP, Brazil) Cornejo, Carlos .Minerals & precious stones of Brazil. Carlos Cornejo...pedras preciosas do Brasil Bibliography 1. Gemology 2. Geology 3. Minerals - Brazil 4. Minerals- Classification... Mineralogy 6. Mineralogy - Brazil - History 7. Precious stones - Brazil I. Bartorelli, Andrea. II. Title |  | | Book | | Occurrence: The Americas 63 USA 64 Mexico 72 Panama 75 Brazil 75 Canada 80 7 Occurrence: Rest of the world 81...all rock types and in most countries. CHALCEDONY Agate (light to dark colours in concentric bands, translucent)...translucent), fire agate (dark agate with play of colour similar to that in opal, opaque), moss agate (pale yellow...quartz crystals come from the State of Minas Gerais, Brazil, and occur in vugs or pockets which are found in...the categories Silex or Kieselstein (including agate, flint opal), Petrosilex or Halleflinta (for jasper |  | | Book | | Yuanming Pan Mineralogy, Geochemistry and Genesis of Agate—A Review Reprinted from: Minerals 2020, 10, 1037.... . . . . 5 Terry Moxon and Galina Palyanova Agate Genesis: A Continuing Enigma Reprinted from: Minerals...Gemological Characteristics and Origin of the Zhanguohong Agate from Beipiao, Liaoning Province, China: A Combined...source of the silica required for the growth of agate remains largely unknown. The first known descriptive...exists today. The complex, multi-step process of agate formation is not yet completely understood. The |
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Oco geode deposits, Três Pinheiros, Fontoura Xavier, Rio Grande do Sul, Brazil