 | Hartmann, Léo Afraneo, da Cunha Duarte, Lauren, Massonne, Hans-Joachim, Michelin, Cassiana, Rosenstengel, Leonardo Manara, Bergmann, Magda, Theye, Thomas, Pertille, Juliana, Arena, Karine Rosa, Duarte, Sandro Kucera, Pinto, Viter Magalhães, Barboza, Eduardo Guimarães, Rosa, Maria Luiza C.C., Wildner, Wilson (2012) Sequential opening and filling of cavities forming vesicles, amygdales and giant amethyst geodes in lavas from the southern Paraná volcanic province, Brazil and Uruguay. International Geology Review, 54 (1) 1-14 doi:10.1080/00206814.2010.496253 | Journal (article/letter/editorial) | | giant amethyst geodes in lavas from the southern Paraná volcanic province, Brazil and Uruguay a b c...giant amethyst geodes in lavas from the southern Paraná volcanic province, Brazil and Uruguay, International...giant amethyst geodes in lavas from the southern Paraná volcanic province, Brazil and Uruguay Léo Afraneo...hydrothermal minerals, particularly the spectacular amethyst, calcite, and gypsum-bearing geodes. Keywords:...Keywords: vesicles; amygdales; giant geodes; amethyst-quartz; Serra Geral Group Introduction The opening and |  | Duarte, Lauren C., Hartmann, Leo A., Ronchi, Luiz H., Berner, Zsolt, Theye, Thomas, Massonne, Hans J. (2011) Stable isotope and mineralogical investigation of the genesis of amethyst geodes in the Los Catalanes gemological district, Uruguay, southernmost Paraná volcanic province. Mineralium Deposita, 46 (3) 239-255 doi:10.1007/s00126-010-0323-6 | Journal (article/letter/editorial) | | of the genesis of amethyst geodes in the Los Catalanes gemological district, Uruguay, southernmost Paraná...the world-class amethyst-geode deposits of the Los Catalanes gemological district, Uruguay, constrain processes...silica minerals in geodes (chalcedony, quartz, and amethyst) are much larger and the values generally somewhat...producers of amethyst and agate geodes (600 tons/month) are Brazil (Ametista do Sul) and Uruguay (Los Catalanes)...deposit geology. In the Serra Geral Group, giant amethyst geodes and agate geodes occur in volcanic rocks |  | Hartmann, L.A., Medeiros, J.T.N., Baggio, S.B., Antunes, L.M. (2015) Controls on prolate and oblate geode geometries in the Veia Alta basalt flow, largest world producer of amethyst, Paraná volcanic province, Brazil. Ore Geology Reviews, 66. 243-251 doi:10.1016/j.oregeorev.2014.11.005 | Journal (article/letter/editorial) | | Veia Alta basalt flow, largest world producer of amethyst, Paraná volcanic province, Brazil L.A. Hartmann...2014 Available online 13 November 2014 Keywords: Amethyst geode Veia Alta flow Prolate Oblate Hydrothermal...fundamental control on the shape and size of the amethyst geodes. The loss on ignition (LOI) of the host...Introduction The presence of both prolate and oblate amethyst geodes in the Paraná volcanic province (Fig. 1)...because this flow is the largest world producer of amethyst geodes (500 t/month in 2014). Commonly, a prolate |  | Gilg, H. Albert, Krüger, Yves, Taubald, Heinrich, van den Kerkhof, Alfons M., Frenz, Martin, Morteani, Giulio (2014) Mineralisation of amethyst-bearing geodes in Ametista do Sul (Brazil) from low-temperature sedimentary brines: evidence from monophase liquid inclusions and stable isotopes. Mineralium Deposita, 49 (7) 861-877 doi:10.1007/s00126-014-0522-7 | Journal (article/letter/editorial) | | 1007/s00126-014-0522-7 ARTICLE Mineralisation of amethyst-bearing geodes in Ametista do Sul (Brazil) from...provide novel insights into the genesis of giant amethyst-bearing geodes in Early Cretaceous Paraná continental...Monophase liquid inclusions in colourless quartz, amethyst, calcite, barite and gypsum were analysed by microthermometry...organotrophic bacteria. During the subsequent stages II (amethyst, goethite and anhydrite), III (early Editorial...homogenisation temperatures and in δ18O values of amethyst show evidence of repeated pulses of ascending |  | | Journal (article/letter/editorial) | | W ord to the Wise Geode JOHN RAKOVAN Department of Geology and Environmental Sciences Miami University...two balls of okenite (not a geode) from the Pune district, Maharashtra, India. The rounded shape of the...(fig. 3), which are common in Mexico, Brazil, Uruguay, and other countries, are essentially large amygdules...These include the sometimes very large elongate amethyst geodes called “cathedrals.” Thus, one way to distinguish...amethystbearing geodes from Los Catalanes Gemological district, Artigas, Uruguay, southern Paraná Magmatic |  | | Journal (article/letter/editorial) | | province, occurring mostly in Brazil but also in Uruguay, Argentina, and Paraguay (Figure 1). The volcanic...volcanic rocks and the formation of the giant amethyst geodes in the Paraná volcanic province (see Duarte...the first basalt flow, e.g. Los Catalanes gemological province, Uruguay, and Quaraí mining province,...m stratigraphic height (Ametista do Sul mining district, Brazil) and even higher (SW Paraná state, 1800...establish the volcanic stratigraphy in Quaraí and Los Catalanes (Hartmann et al. 2010), in Torres (Hartmann |  | Fritsch, Emmanuel, Rondeau, Benjamin, Devouard, Bertrand, Pinsault, Lauriane, Latouche, Camille (2017) Why Are Some Crystals Gem Quality? Crystal Growth Considerations On the “Gem Factor”. The Canadian Mineralogist, 55 (4) 521-533 doi:10.3749/canmin.1700013 | Journal (article/letter/editorial) | | complementary, favorable factors. We propose a unique gemological perspective, a field of science where specialists...model is not often reported for gems in the gemological literature, although it is common. It may be...luminescence techniques. This approach, now routine in gemological laboratories, reveals that the majority of near-colorless...accumulation (London 2008, Simmons et al. 2012). Amethyst crystallizes on the walls of geodes formed in...formation of amethyst-bearing geodes from Los Catalanes gemological district, Artigas, Uruguay, southern |  | Baggio, Sérgio Benjamin, Hartmann, Léo Afraneo, Lazarov, Marina, Massonne, Hans-Joachim, Opitz, Joachim, Theye, Thomas, Viefhaus, Tillmann (2018) Origin of native copper in the Paraná volcanic province, Brazil, integrating Cu stable isotopes in a multi-analytical approach. Mineralium Deposita, 53 (3) 417-434 doi:10.1007/s00126-017-0748-2 | Journal (article/letter/editorial) | | America, mainly Brazil but including portions of Uruguay, Argentina, and Paraguay (Fig. 1). The volumes...azurite, resembling those in the Vista Alegre district (Pinto et al. 2011b). In Santa Catarina state...crystal of specimen VA1 from Vista Alegre mining district, Vista Alegre, Rio Grande do Sul state. d Detail...metal source needs to be considered. In the MI district, this issue has been discussed for over a century...crusts. Studies in monophase fluid inclusions in amethyst deposits (Gilg et al. 2003; Duarte et al. 2009; |  | Voudouris, Panagiotis, Melfos, Vasilios, Mavrogonatos, Constantinos, Tarantola, Alexandre, Gӧtze, Jens, Alfieris, Dimitrios, Maneta, Victoria, Psimis, Ioannis (2018) Amethyst Occurrences in Tertiary Volcanic Rocks of Greece: Mineralogical, Fluid Inclusion and Oxygen Isotope Constraints on Their Genesis. Minerals, 8 (8) 324 doi:10.3390/min8080324 | Journal (article/letter/editorial) | | minerals Article Amethyst Occurrences in Tertiary Volcanic Rocks of Greece: Mineralogical, Fluid Inclusion...15126 Athens, Greece; dimitrisal@hotmail.com Department of Earth Sciences, St. Francis Xavier University...Epithermally altered volcanic rocks in Greece host amethyst-bearing veins in association with various silicates...alternations of amethyst, chalcedony and/or carbonates is a common characteristic of the studied amethyst-bearing...propylitic and zeolitic types. Precipitation of amethyst took place from near-neutral to alkaline fluids |  | Baggio, S.B., Hartmann, L.A., Andrade, R.H.P., Rizzotto, G.J., Duarte, S.K., Knijnik, D.B., Simões-Neto, J.A. (2015) Basalt stratigraphy and silica gossans in Campo Grande and Serra de Maracaju, Mato Grosso do Sul, Paraná Volcanic Province. Ore Geology Reviews, 69. 73-87 doi:10.1016/j.oregeorev.2015.01.015 | Journal (article/letter/editorial) | | strongly indicating the presence of calcite, amethyst and agate geode deposits along with native copper...geochemistry to readily locate favorable areas for MA amethyst and agate geode deposits and native copper mineralization...of 917,000 km2 (Frank et al., 2009) in Brazil, Uruguay, Argentina and Paraguay (Fig.1) with a lava volume...magma types. The world´s MA largest deposits of amethyst and agate are hosted in rocks from the two magma...concentrated in Ametista do Sul in Brazil and Los D Catalanes in Uruguay (Juchem et al., 2010; Silva, 2010). |  | Arena, K.R., Hartmann, L.A., Baggio, S.B. (2014) Geological controls of copper, gold and silver in the Serra Geral Group, Realeza region, Paraná, Brazil. Ore Geology Reviews, 63. 178-200 doi:10.1016/j.oregeorev.2014.05.005 | Journal (article/letter/editorial) | | southern Brazil and are well known as host rocks of amethyst and agate mineralization and occurrences of native...The Serra Geral Group is the host of world class amethyst and agate deposits and may also contain large...silicon deposited as valuable silica minerals (e.g., amethyst), copper as a native metal (Hartmann et al., 2010;...protogeodes and their filling with amethyst and agate. The main deposits of amethyst and agate (Duarte et al.,...LeHuray, 1989) is comparable to the Vista Alegre district (Pinto et al., 2011a) in the Paraná volcanic province |  | | Journal (article/letter/editorial) | | copper and supergene enrichment in the Vista Alegre district, Paraná basaltic province, southernmost Brazil...copper and supergene enrichment in the Vista Alegre district, Paraná basaltic province, southernmost Brazil...copper and supergene enrichment in the Vista Alegre district, Paraná basaltic province, southernmost Brazil...occurrences (n = 85) that forms the Vista Alegre district in the border region of Rio Grande do Sul and...basaltic province; PGE analyses; Vista Alegre district Introduction Deposits dominated by native copper |  | | Journal (article/letter/editorial) | | vein, Lucky Friday mine, Coeur d’Alene mining district, U.S.A—Patrick Nadoll and Jeffrey L. Mauk 261...brecciated Se–Chahun iron oxide-apatite deposit, Bafq district, Iran: Insights from paragenesis and geochemistry—Zahra...study of the Kairagach gold deposit, Kurama ore district, central Tien Shan—I.V. Chernyshev, V.A. Kovalenker...and temporal-spatial framework of the Yueshan district, Anhui province, east-central China—Lejun Zhang...(gold) ore-forming model for the ShaxiChangpushan district, Lower Yangtze metallogenic belt, China: Geological |  | | Journal (article/letter/editorial) | | 3749/canmin.1900028 THE GENESIS OF AGATES AND AMETHYST GEODES INGRID N. KIGAI§ Institute of Geology of...of agates and the related famous amethyst geodes of Brazil and Uruguay. Agates form over a wide range of...carbonate rocks and the famous amethyst druses of Brazil and Uruguay formed at the moderate temperatures...extrusion channels, moss textures, lithophysae, amethyst geodes. INTRODUCTION The genesis of agates invariably...and (10) the environment of formation of giant amethyst geodes. These issues are revisited here. THE |  | | Journal (article/letter/editorial) | | occurrence is located in the NW of Chemnitz in the district Altendorf (sample ChemACh). Here, bluish vein...agates both wall-lining banding and horizontal Uruguay banding exist. RI St. Egidien, about 7 km west...show parts with horizontally layered agate bands (Uruguay agate). The agates in general show varying amounts...polymeri- SC The formation of horizontally layered Uruguay agates is different and can be explained by the...of the genesis of amethyst geodes in the Los Catalanes gemological district, Uruguay, southernmost Paraná |  | | Journal (article/letter/editorial) | | 40, 09599 Freiberg, Germany; r.moeckel@hzdr.de Department of Geological Sciences, University of Saskatchewan...Recent have shown that Oregon opal‐CT,(USA), opal‐C,Los cristobalite and moganite are also common in agates...agates from the Richardson Ranch, Oregon (USA), Los Indios (Cuba), Sidi Rahal (Morocco) and Jalgaon/Savda...(II) horizontally layered agates agates (“Uruguay (“Uruguay conforming the 7a), and horizontally layered...(Chihuahua, Mexico); (b) horizontal banding (“Uruguay agate”) in an agate from Bightbridge, Simbabwe; |  | | Book | | Dimitrios Alfieris, Victoria Maneta and Ioannis Psimis Amethyst Occurrences in Tertiary Volcanic Rocks of Greece:...varieties (e.g., opal, chalcedony, agate, quartz, amethyst). Following the fundamental idea of the Special...Götze, J.; Alfieris, D.; Maneta, V.; Psimis, I. Amethyst occurrences in Tertiary volcanic rocks of Greece:...Freiberg, Brennhausgasse 14, 09596 Freiberg, Germany Department of Geological Sciences, University of Saskatchewan...paramagnetic resonance spectroscopy of Fe3+ ions in amethyst: Thermodynamic potentials and magnetic susceptibility |  | | Book | | Dimitrios Alfieris, Victoria Maneta and Ioannis Psimis Amethyst Occurrences in Tertiary Volcanic Rocks of Greece:...varieties (e.g., opal, chalcedony, agate, quartz, amethyst). Following the fundamental idea of the Special...Götze, J.; Alfieris, D.; Maneta, V.; Psimis, I. Amethyst occurrences in Tertiary volcanic rocks of Greece:...Freiberg, Brennhausgasse 14, 09596 Freiberg, Germany Department of Geological Sciences, University of Saskatchewan...paramagnetic resonance spectroscopy of Fe3+ ions in amethyst: Thermodynamic potentials and magnetic susceptibility |  | | Book | | . . . 83 Xuemei Zhang, Lei Ji and Xuemei He Gemological Characteristics and Origin of the Zhanguohong...Sciences. She is currently a lecturer at the Department of Mineralogy and Geochemistry of Novosibirsk...hosted by Paleocene/Eocene tuffs from El Picado/Los Indios, Moa region (the Eastern part of Cuba). The...10, 198. [CrossRef] Zhang, X.; Ji, L.; He, X. Gemological Characteristics and Origin of the Zhanguohong...40, 09599 Freiberg, Germany; r.moeckel@hzdr.de Department of Geological Sciences, University of Saskatchewan |  | | Book | | razoável background em ciência de quem busca lê-los e interpretá-los. Tal profundidade de tratamento reflete...história e uma dinâmica particulares, mas para ajudá-los a tomar decisões sobre temas ambientais de grande...longo deste livro, assim, é oportuno caracterizá-los de modo mais preciso. São eles: o embasamento, a...necessariamente incluído em outra; individualizá-los é, muitas vezes, impossível. Por outro lado, a classificação...difíceis de reconhecer e tem a vantagem de separá-los daqueles que observamos diretamente ou temos notícia |
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