Discovery of Pyrope Spessartite garnets ( Madagascar )Written by Alain Darbellay GGGems
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At this time started orange garnet's fever. The stone did not show almost any more change, its champagne-orange color at day was simply reinforced in a vivid orange or for other elements in an orange-red under electric light. This type of garnet is a pyrope-spessartite also containing vanadium and chromium traces. On totality of Malaya extracted, a small part was pure, but much showed typical inclusions of this stone. Initially networks of rutile needles and strain patterns were often present, and inclusions of graphite accompanied them. Negative crystals and, quartz, apatite, monazite and zircon had been also invited during growth of precious malaya garnet. Here first pyrope-spessartite cut in 1998. Realized in an arid landscape composed of bushes and cactus, this discovery remains exceptional by quality of its product and also by fact that it was second deposit in world to deliver this type of Malaya garnet. Here, one of only intact garnets found in occurrence. Its unusual stacking shape must be noticed. Refractive Index: 1.73 - 1.81 Chemical Composition: [Mg3 + Mn3]AL2(SIO4) Hardness: 7 - 7.5 Density: 3.65 - 4.20 Crystal Group: Cubic Above, only phlogopite mica found in neighborhood of deposit at that time, it is still in its gangue. Of transparent quality, it shows a similar color to that of malaya garnets. ¦ Garnet data ¦ Madagascar Gem Safari ¦ Malaya garnet Catalog ¦ All pictures on this site have been shot by gggems.com Alain Darbellay © 1987 - 2004 gggems.com All rights reserved.
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| | Madagascar corundums ( Sapphire & Ruby discovery )Written by Alain Darbellay GGGems
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Ruby in amphibolite. The crystals engaged in rocks, rich in mica have rough faces, encrusted of biotite or muscovite, minerals which also exist at state of inclusions, associated with magnetite and pyrite. Because of its hardness, its inalterability and its density, corundum constitutes a standard mineral of alluvia. Ruby Giant Sapphire in a metamorphic dolomitic limestone. Polychrome Sapphire Blue Sapphire ( origin: Blue Sapphire ( origin: Ilakaka 1999 ) ( origin: Iankaroka 1990 ) Andranondambo 1992 ) Found in sandstones of Isalo in This sapphire comes from a granit, The stone comes from alluvium, shape is rounded. its shape is intact. a metamorphized limestone. The origin of stone is a limestone. · The structure of crystals. It is R.J.Haüy who put forth first assumption, confirmed 200 years later, on structure of crystallized material. He lets drop accidentally a calcite crystal which broke into small rhomboedrons. He supposed whereas crystals were consisted of stacking small rhomboedrons elementary (that he called "integral molecule"), he could reconstitute all known shapes of calcite. In a crystal lattice, three atoms or groups of atoms (nodes), which is not on same line, determine a plan called reticular plan. But there is a great number of these plans: it is enough to choose nodes not strictly nearby. As network is infinite, there is even an infinity of possible plans. The dimension of faces does not play of role. In course of growth, a face can develop more quickly than another. The angle that faces make between them remains constant, since it depend on network. This structure of crystalline material explains law of constancy of dihedral angles. Triangular figure on a Scratches on a rare Stacking in macle Triangles on a translucent colorless corundum. colorless corundum. of a ruby. corundum. Triangular figure on a Triangles in step on a blue Remarkable macle of blue corundum. corundum from Maromby. red corundum. Sapphire & Ruby Safari Gem ruby from Ambatovaravarana. The alluvial ruby deposit of Ambatovaravarana in high plateaus, is in left center on picture, under hill. Macle of blue sapphire. Macle of ruby 60 grms. Information ¦ Cutting Styles ¦ Characteristics ¦ Crystalline Systems ¦ Madagascar Sapphire Andranondambo Sapphires ¦ Blue Sapphire Crystal ¦ Ruby Crystal ¦ Sapphire Slice Your guide to GGGems.com All pictures on this site have been shot by gggems.com Alain Darbellay © 1987 - 2004 gggems.com All rights reserved.
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