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| harvested from the Caribbean islands off the coast of Venezuela during the early 16th century, to determine their...Flux-grown pink synthetic sapphire with unusual crystal inclusions pg. 371 369 G&G Micro-World Unusual...• Growth tube cluster in sapphire • Quarterly crystal: Barite in fluorite 373 Gem News International...Blue-green pyrope-spessartine with high vanadium • “La Lechuga” monstrance • “Montana Queen” sapphire •...gemologist at Centro de Desarrollo Tecnológico de la Esmeralda Colombiana (CDTEC), and his GIA coauthors provide |
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| resulting classification system. The 10.5 ct emerald crystal in this gold and platinum pendant is from Jos,...Rodrigo Giraldo, Centro Gemológico para la Investigación de la Esmeralda, Bogotá; Carlos Osorio, Mineralco...polycrystalline synthetic diamond films and single-crystal synthetic diamond. These methods may provide important...polycrystalline synthetic diamond films and single-crystal synthetic diamond also can be applied to natural...diamond showing the alexandrite effect. Journal of Crystal Growth, Vol. 193, pp. 577–584. Moses T.M., Shigley |
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| Scienze della Terra, Università degli Studi di Roma 'La Sapienza', P. le A. Moro 5, 00185 Roma, Italy ****Benzeholzstrasse...and parallel to the rhombohedral faces of the crystal. These directions of weakness can probably be ascribed...ascribed to a lamellar twinning structure. 8x. crystal growth. Occasionally, an amount of titanium in...chemico-physical variations of the host J. Gemm., 1989,21,8 crystal growth conditions and in some cases causing a hazy...mother-fluid penetrated into fractures of the embedding crystal, and iron compounds have been segregated. The irregular |
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| 9-7;o)+o Icassi1ite~9~7,O)+O Chatham, USA CR Crystal Res.Com.,Australia O extra flinty o extra dersedense...not conclusively proved. Whatever the nature of rock associated with diamond recovery, whether sandstone...rarely is diamond found embedded in the actual parent rock wherein it was formed. I n instances where diamonds...developed, methane is passed over a diamond seed crystal at temperatures of about 2,000°F. T h e gas decomposes...the crystal. T h e carbon atoms arrange themselves in the same atomic pattern as the seed crystal and |
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| Modern emerald and beryl jewellery Chapter 4 67 Crystal structures and chemical composition The beryl structure...Morganite (pink) 1.586-—1.594 Chemical composition Crystal system Optical clarity Be3Al.(SiO3), Hexagonal...the difficulty of recovering emeralds from hard rock without fracturing the crystals. Compared to Colombian...necklace beads, mixed with beads of amethyst and rock crystal, in many cases these emeralds are not cut; the...the natural hexagonal form of the crystal 1S preserved, and nothing is done to the gem except that a |
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| Modem emerald and beryl jewellery Chapter 4 67 Crystal structures and chemical composition The beryl structure...5 2.66 7.5 2.68 7.5 2.80 7.5 2.85 7.5 Crystal system Optical clarity Hexagonal Transparent...the difficulty of recovering emeralds from hard rock without fracturing the crystals. Compared to Colombian...necklace beads, mixed with beads of amethyst and rock crystal. in many cases these emeralds are not cut; the...the natural hexagonal form of the crystal is preserved, and nothing is done to the gem except that a |
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| Berkshire RG 11 2PY, England Yan Nostrand Reinhold 480 La Trobe Street Melbourne, Victoria 3000, Australia...£species Minerales de Jalisco; D. Santiago Ramirez's La Riqueza Minera de Mexico, and his translation of...(Fig. 1) produced specimens from such places as the La Fe Mine in the state of Chiapas and Santa Rosalia...took refuge in a remote side canyon of the Sierra de la Santa Eulalia where they accidentally rediscovered...considered to be the bonanza days of the Real de la Santa Eulalia. A small n1ining cc:1mp, located below |
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| Berkshire RG11 2PY, England Van Nostrand Reinhold 480 La Trobe Street Melbourne, Victoria 3000, Australia...Especies Minerales de Jalisco; D. Santiago Ramirez’s La Riqueza Minera de Mexico, and his translation of...pa Biren vem, nM cad tomas ies ery £5 ao hebe, La iOd aay Am gle Pha yy i;sian, WRT a ss] ae " re...(Fig. 1) produced specimens from such places as the La Fé Mine in the state of Chiapas and Santa Rosalia...took refuge in a remote side canyon of the Sierra de la Santa Eulalia where they accidentally rediscovered |
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| accompanied by metallic oxides such as spéculante. This rock is very similar to the matrix of the topaz. Euclase...is the most common, whereas the violetcoloured crystal is the rarest. If the crystals were flawless, free...formula being Be(A10H)SiC>4. T h e faces of the crystal are smooth. Euclase belongs to the monoclinic system...colour is obtained by a correct orientation of the crystal. W h e n the stones have the light blue colour...were found a n d continue to be found in the rock crystal. From the old mine called Morro came some of |
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| abundant structure is produced as light entering the crystal causes the phosphate groups to vibrate within only...yellow and the green components and leaves the crystal blue. We must also determine, then, how the heat...faceted gems. One would have to have a very thick crystal to see the color brought about by iron in the aluminum...ions, which run parallel to the c-axis of the crystal. If the iron present in these channels is in the...obtained with light polarized along the c-axis of the crystal; the spectrum illustrated by the broken line was |
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| many other enchanting exhibits and sales. Have a crystal en counter at "C,ystol Holl", the largest 8!CIJ1bltlon-sale...native (her brother Peter, who introduced her to rock music, is now Police Chief), as are Barbara Eden...Sanders Gallery also has a branch nearby at the Westin La Paloma resort, 3800 E. Sunrise. Performances Arizona-Sonora...dining there is Keaton's (at FoothilJs Center, 7401 N. La Cholla Blvd . , 297- 1 999), popular as well with...particular ly Sbarro's (in Foothills Center, 740 1 N. La Cholla Blvd.). Personally we stay away from the chain |
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| zigzag cleavage • HPHT-grown synthetic diamond crystal with unusual morphology and negative trigons •...amazonite in Mexico • Astorite—A rhodonite-rich rock from Colorado • Color-change bastnäsite-(Ce) from...cuberelated shape from the Jwaneng mine,” Journal of Crystal Growth, Vol. 94, 1989, pp. 229–252). This terminology...presque cubiques: Quelques définitions utiles sur la morphologie,” Revue de Gemmologie a.f.g., Vol. 153... Central African Republic, Tanzania, Brazil, Venezuela, Guyana, China, United States, India, and Indonesia]); |
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| mantle lies the Earth’s crust, a ‘thin’ skin of rock, less dense than the mantle, and derived from it...wide range of simple to complex rock structures. This range of rock types and their inter-relationships...inorganic, with a specific chemical composition and crystal structure. Minerals with the qualities of beauty...mantle are so hot that parts may melt to form molten rock or magma. When magma cools, it forms igneous rocks...major influence on the appearance and texture of the rock. Deep underground, slow cooling allows time for |
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| Currently the term 'black jade' may include Figure la,b: Black jadeite jade bangles. © Gemmological Association...pure jadeite (J in As shown in Table I, the whole-rock Table I) to omphacitic jadeite (OJ) to jadeitic...Composition of black jadeite. wt.% Analysis of rock 1 Electronmicroprobe analyses ofjadeite grains...100.687 100.938 JO I OJ JO J OJ JO Notes: Rock analysis (1) by the National Research Center of...distinguished: 1. Brown inclusions may be on particular crystal faces of the jadeite grains or dispersed at random |
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| the structure, and of lore. Christian the crystal color. lan- signif- chemical optical properties...part is anywhere an beryl deposits, of fine crystal Sinkankas has in the literature, encyclopedic...90 Emerald Lore in Colombia and Peru, 5. 93 Crystal Structure Chemical Composition of and Beryl...Beryl emeralds generally from those of hard rock without Egypt were fracturing the quite small...emerald, topaz, rock title page of S are diamond (top left) sapphire, chry- crystal (top right). |
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| and isomorphism The classification of minerals Crystal structure Properties of crystals Gem crystals ...imitation stones Crystal growth from solution Growth by flame-fusion Hydrothermal growth Crystal pulling Flux-melt...corundum precipitates out in star-like rays when the crystal is heated to approximately 1500°C (the melting...arbitrarily assigned as 12. birefringence a crystal with more than one refractive index is said to...there. defect an internal irregularity in a crystal. dendritic having a plant-like form. dislocations |
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| Turquoises: les bonnes, les brutes et les traitées. La Recherche, No. 163, pp. 244–247. Dontenville S.,...GEMOLOGY Spring 1999 17 Figure 1. Russian crystal-growth laboratories are now producing hydrothermal...(Verneuil) seeds specifically for the study of crystal growth. The eight crystals ranged from about 6...polished window was prepared on about 15 of the crystal fragments (the largest of which was 41 ct) for...various oblique angles to the c-axis of the original crystal. Consequently, we determined the pleochroism of |
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| Guajira Tairona Lower Magdalena Atlantic watershed Venezuela Greater Nicoya Costa Rica Panama Chiriquí...1200 1100 Late Ceramic E Late Ceramic D Cartago La Cabaña Chiriquí Late Ceramic C Sapoá 1000 900...700 600 500 Chiriquí Curridabat Late Ceramic A La Selva Aguas Buenas Bagaces 400 300 Aguas Buenas...Middle Ceramic C Middle Ceramic B El Bosque Pavas La Concepcíon Middle Ceramic A 0 100 B.C. Tempisque...400 500 600 700 Early Ceramic B 800 900 Barba La Montaña Sinacrá 1000 1100 1200 1300 Orosi 1400 |
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| Academia de ciencias me'dicas, fisicas y naturales de la Habana (Cuba) Anales vols. 70-75. Habana, Cuba. Academy...Bulletins 1-5; Information Circulars 1-11. Little Rock, Ark. Association of American Geographers Annals...vols. 1-5. Augustana Library Publications 13, 16. Rock Island, 111. Auk vols. 43-56, 1926-39. Lancaster...1-16. New Orleans, La. Louisiana Conservation Review vols. 1-8 (no. 3). New Orleans, La. Louisiana Engineering...Proceedings vols. 21 (nos. 4, 6), 22-25. New Orleans, La. Maine State Geologist 1st, 2d Annual Reports. Augusta |
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| Protestantisme frangais. Author of Les Precurseurs frangais de la tolerance; Histoire de I’etablissement des protestanls...Archives, Paris. Officer of Public Instruction. of La France sous Philippe VI. de Valois; &c. J. V. B... Profit; Garden and Farm Topics. P. H. P.-S. P. La. { Holies, Baron. Horticulture: American Author...A common and character¬ istic form of twinned crystal, such as is represented in the figure, con¬ sists...twin-laws; the compound group resembles a tetragonal crystal with prism and pyramid, but may be distinguished |
