 | | Journal (article/letter/editorial) | | June 29, 2016 REV. R. BARON ON THE GEOLOGY OF :MADAGASCAR. 305 18. N o ~ s on the GrozooY 0fM*DXGASCAR...] [PLATESXIII. & XIV.] GE~-ERAL DESCRIPTION. MADAGASCAR is as yet almost a terra incognita to the geologist...of this great island. The central portion of Madagascar is generally regarded as consisting chiefly of...by far the greater part of the eastern half of Madagascar consists of gneiss and other crystalline rocks...of the island ~. Hence the roads from Central Madagascar to the east run over an endless series of more |  | | Book | | 8 Front cover: A Spessartite garnet in mica, Madagascar (Sorbonne collection) 0.08 inch. B Tourmaline...(Sorbonne collection) 6 inches. Right: Rutile in quartz, lbitiara, Bahia, Brazil (Yves Gillet collection...case of rhodochrosite. 10 Amazonstone and smoky quartz, Lake George, Park Co., Colorado (Coil family-...levels of artistry with much harder minerals such as quartz, carnelian, lapis-lazuli, etc. Phenicians, Cretans...from Persia, jade from China, opal from Hungary, quartz from the Alps, agates and carnelians from various |  | | Journal (article/letter/editorial) | | PEGMATITES OF THE ANTSIRABE-KITSAMBY DISTRICT, MADAGASCAR WESTON BOURRET* Box 409, Pauma Valley, CA 92061...pegmatites of the Antsirabe-Kitsamby district, Madagascar. In: J.W. Gabelman (Editor), Unconventional Uranium...Uranium Deposits. Ore Geol. Rev., 3:177-191. Madagascar, sixth largest island in the world, is about...euxenite-bearing Tertiary lake sediments near Vinaninkarena, south of Antsirabe in Central Madagascar. Interest in...pegmatites are identified by a central massive quartz core in deeply lateritized terrain. In simplest |  | | Report (issue) | | The Natural History Museum of Milan and its Madagascar Collection The Museo Civico di Storia Naturale... the museum began paleontologic fieldwork in Madagascar (upper Permian fauna and Jurassic and Cretaceous...fieldwork in Madagascar in 1996 in collaboration with other institu tions in Madagascar, Italy, and the...Pezzotta has spent a total of twenty nine months in Madagascar making geological-mineralogical surveys. In collaboration...watercolor by Valter Fogato Title Page Photos Quartz crystal with hematite from Mangatobangy, IO cm |  | | Book | | many people who, on seeing a crystal of pyrite or quartz, can scarcely believe that it is the work of Nature...before our very eyes, as a result of deposits in sea, lake and river water, often under the influence of biological...equals 2.54 centimeters. Carbon Diamond Silica Quartz and its varieties Opal Amethyst Common or rare...Prehnite 44 Pronsite 64 Pyrite 60 Pyromorphite 78 Quartz and its varieties . 16 Realgar 66 Rhodocrosite.... ; L *'/ I . ' ' 1 Silica Quartz and its varieties Quartz consists of a combination of the two |  | | Journal (issue) | | and star garnet cat's-eyes from Ambatondrazaka, Madagascar Dr Karl Schmetzer 1 , Dr Heinz-Jürgen Bernhardt...properties of star garnets from Ambatondrazaka, Madagascar, are given. All samples examined are intermediate...garnets have been offered in local markets in Madagascar since about 1997. The rough materials for these...of Ambatondrazaka which is located south of Lake Alaotra, about 160 km north-east of the capital Antananarivo...habit of garnet crystals from Ambatondrazaka, Madagascar, showing only the dodecahedron crystal form {110}: |  | | Catalog/List | | ALMANDINE Large brown well fom1ed dodecahedral Madagascar I ins£4 garnet group Crystal I inch across ALSTONITE...IxI£-l Flux Canyon.Sanln Cruz Rich orange masses in quartz. under 1/, x ½ £2 y K Al S0/4 OH _ _ magnification...__ County. _ AI1zona 60 AMAZO:-;ITE 2x3i nch£5 Madagascar Anractive green with white penhitic _Feldsp�ar...Comwall large I x2 Quilc rich. blue-grey masses in Quartz APATITE Ca PO/4 F wi1h minor Mica __ ___ __ --...----·Carrock Mine Cumbria l x l £I .SO J x2 £3 Greenish in Quartz _ Woll nuoresee pale APA TITE F L U O R E S C_E_N_T_ |  | | Journal (issue) | | Libethenite (Zambia), v.10/#1 Hydroxylherderite Quartz & Pyrite (WA), (Brazil), Bookson U.S. Hydroboracite... v.14/#1 Celestite (IN), v.13/#4 Diamond (CO), Quartz Derbyshire (England), (MT), Jeanbandyite. $12 Bancroft... $12 v.10/#3 Taewha mine (Korea) Japan Twins (Quartz), Bancroft (Ont.), Franklin $12 v.12/#1 Iceland...Idria mines (Yugoslavia), Outlaw Seriphos (Greece), Lake George Eugui quarries (Spain) $12 mine (NV), Pribram... v.20/#3 Ouro Preto (Brazil), Anjanabonoina (Madagascar), $12 Port Radium Silver (Canada) $12 v.25/#1 |  | | Book | | second piece: the flakes are mica, the glassy grains quartz, and the yellowish grains feldspar. The whole specimen...hich feldspar, quartz, and mica are the main constituents. Quartzite consists of quartz only, mica schist...schist of quartz and mica, and eclogite of garnet and augite. There are also rocks which consist of fragments...100,000 years ago, beads made of limestone and quartz were found, and when man began to decorate cave...hexagofja/ and trigomiiPI. 12corundum, Pls. 14- 17 quartz, Pls. 22, 23 calcite, Pl. 30 apatite and -pyromorphite |  | | Journal (issue) | | Chalcedony itself is a highly compacted form of quartz that forms in micro- • scopically small crystals...of them are concealed within large crystals of quartz), but when the outer layers are split open they...silicate group of minerals and gemstones. Like quartz, of whic h it is one of the many forms, agate is...material is now imported into Germany from the huge quartz deposits that have been discovered in the last...been found in China, Egypt, the Italian Alps, Madagascar and Mexico. Agate has also been found in parts |  | | Book | | Staurolite 179 Steatite Pyrope WA Succinite Quartz 180 Sugilite Rhodizite 186 Rhodochrosite Rhodolite...Garland, J. Amster of the Compagnie Générale de Madagascar, J. Sirakian of the Taillerie de Royat, and S...Chibcha of South America offered gold and emeralds to Lake Titicaca (see EMERALD). Tribal chiefs, priests,...owner's rank. Gems as Trademarks and Tokens Intaglio quartz scarab with the cartouche of the Egyptlan king...inexpensive processes that separated materials Quartz crystals from Corinto, Minas Gerais, Brazil. Height: |  | | Journal (issue) | | Euclase from Brazil Inclusions in Demantoid from Madagascar Photochromism Part 2 Volume 38 / No. 1 /...Demantoid Garnet from Antetezambato, Northern Madagascar—Internal Characteristics and Their Use in Deciphering... Štubňa Gem Notes Aquamarine from Manakana, Madagascar | Star Augite from Vietnam | Crocoite from Tasmania...COLOURED STONES Aquamarine from Manakana, Madagascar Madagascar is well known as a source of aquamarine...pegmatitic districts on the west side of Lake Alaotra in central Madagascar. In this case, the specific aquamarine |  | | Book | | 97 — The Study of Precious Stones 115 10 The Quartz Minerals and Rocks 133 // The Mineral Resources...study of precious and to the abundant and popular quartz stones minerals and rocks. As a guide to prospecting...prospectors flint, composed of silica like that of quartz, this early ancestor of ours found a substance...have been uncovered in the region of Great Bear Lake in northwest Canada, on the Colorado Plateau, in...United States, the sabi "range" at the for head of Lake Superior, is Megood only another generation or |  | | 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 |  | | Book (edition) | | 20 21 22 23 24 25 26 27 28 29 30 31 Spodumene Quartz Opal Turquoise Lapis Lazuli Jade – Geology and...of glass closely resembling opal in appearance. Quartz, which for many years has been manufactured in...information on a number of topics, particularly on the quartz gems. Mr J Asscher, Jnr, of Amsterdam checked the...pyroxenes, the amphiboles, the micas, the feldspars and quartz. Broadly, these minerals represent the range from...texture shown in thin section and consisting of quartz (clear), feldspar (pale brown, ‘dusty’) and magnetite |  | | Journal (issue) | | Johne FGA, L Joyner PhD FGA, H Kitawaki FGA CGJ, R J Lake FGA DGA, Li Li Ping PhD FGA DGA, M A Medniuk FGA...colour change behaviour have also been found in Madagascar (M.S. Krzemnicki, pers. comm., 2004). 6 Garnet...non-basalt-related deposits in the Isalo area of Madagascar, from Ratnapura, Sri Lanka and from Mogok, Myanmar...non-basalt-related origin (e.g. from Sri Lanka, Myanmar or Madagascar) is now straightforward. However, distinction...as between Thailand and Australia, or between Madagascar, Sri Lanka and Myanmar – are much more difficult |  | | 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,...SUITE Penetration _Tivins ~laurolite, fiuorite , quartz (Brazil and Dauphine), orthoclase. Contact Twins... INTRODUCTION 11 CRYSTALLINE AGGREGATES SUITE Druses Quartz (geode or cavity lining), calcite. G ranu lar Granite | | | 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 | | alivines, pyroxenes, amphiboles, micas, feldspars, and quartz-account for over 90 percent of all igneous rocks...crystallize are potassium feldspar, muscovite mica, and quartz, the major constituents of granite. Finally, water...(Intermediate) ' ~· ( -· , ,. ~ Gobbro (Bo sic) Quartz Muscovite Mica K Feldspar Na Feldspar Pyrox...chemical and mineralogical . Because feldspars, quartz, olivines, pyroxenes, amphiboles, and micas are...the presence or absence of quartz, and, in rocks with no feldspar or quartz, the type of iron and magnesium |  | | 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 |  | | Journal (article/letter/editorial) | | Pyromorphite Pyrophyllite Pyroxmangite Pyrrhotite Quartz, lechatelierite, keatite, stishovite, christobalite...double-triangular plot also called Q–A–P–F diagram (quartz, alkaline feldspar, plagioclase, and foid) designed...wolframite, tetrahedrite and base metal sulfide quartz veins have successfully been used to constrain...feldspar, quartz and some mica. Heavy minerals with specific gravities exceeding that of quartz are minor...Granite characterized by alkaline feldspar and quartz with little or no mafic minerals. Porphyritic igneous | | | Journal (article/letter/editorial) | | Pyromorphite Pyrophyllite Pyroxmangite Pyrrhotite Quartz, lechatelierite, keatite, stishovite, christobalite...double-triangular plot also called Q–A–P–F diagram (quartz, alkaline feldspar, plagioclase, and foid) designed...wolframite, tetrahedrite and base metal sulfide quartz veins have successfully been used to constrain...feldspar, quartz and some mica. Heavy minerals with specific gravities exceeding that of quartz are minor...Granite characterized by alkaline feldspar and quartz with little or no mafic minerals. Porphyritic igneous |  | Gaines, Richard V., Skinner, H. Catherine W., Foord, Eugene E., Mason, Brian, Rosenzweig, Abraham, King, Vandall T. (1997) Dana's New Mineralogy (8th ed.) Wiley-Interscience. p.1872 | Book (edition) | | Especially when the mineral species is common, such as quartz (75.1.3.1), many varieties (jasper, onyx) are known...chemistry and structure are identical to those of quartz. 5D. Polytypes Materials whose basic structural...only with fibrous minerals Columbite, wolframite Quartz Opal, some yellow varieties of sphalerite Nepheline...are distinctive. Chonchoidal fracture, typical of quartz, gives a fracture similar to the interior of a...Calcite 4 5 6 Fluorite Apatite Orthoclase a Quartz Soft, greasy feel like tale and graphite, and |
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Lake Alaotra, Alaotra-Mangoro, Madagascar