Chemical Composition of Gem-Stones | (a) Elements— | | | Diamond | C | | (b) Oxides— | | | Corundum | Al2O3 | | Quartz | SiO2 | | Chalcedony | SiO2 | | Opal | SiO2.nH2O | | (c) Aluminates— | | | Spinel | MgAl2O4 | | Chrysoberyl | BeAl2O4 | | (d) Silicates— | | | Phenakite | Be2SiO4 | | Dioptase | H2CuSiO4 | | Peridot | Mg2SiO4 | | Zircon | ZrSiO4 | | Enstatite | MgSiO3 | | Diopside | CaMg(SiO3)2 | | Nephrite | CaMg3(SiO3)4 | | Sphene | CaTiSiO5 | | Benitoite | BaTiSi3O9 | | Andalusite | Al(AlO)SiO4 | | Kyanite | (AlO)2SiO3 | | Topaz | [Al(F,OH)]2SiO4 | | Epidote | Ca2(Al,Fe)2(AlOH)(SiO4)3 | | Euclase | Be(AlOH)SiO4 | | Prehnite | H2Ca2Al2(SiO4)3 | | Iolite | H2(Mg,Fe)4Al8Si10O37 | | Garnet { | Hessonite | Ca3Al2(SiO4)3 | | Pyrope | Mg3Al2(SiO4)3 | | Almandine | Fe3Al2(SiO4)3 | | Andradite | Ca3Fe2(SiO4)3 | | Beryl | Be3Al2(SiO3)6 | | Spodumene | LiAl(SiO3)2 | | Jadeite | NaAl(SiO3)2 | | Moonstone | KAlSi3O8 | | Tourmaline | 12SiO2.3B2O3.(9-x)[(Al,Fe)2O3].3x[(Fe,
Mn,Ca,Mg,K2,Na2,Li2,H2)O].3H2O | | Axinite | HCa3Al2B(SiO4)4 | | Idocrase | (Ca,Mn,Mg,Fe)2(Al,Fe)(OH,F)]Si2O7 | | (e) Phosphates— | | | Beryllonite | NaBePO4 | | Apatite | Ca5(F,Cl)(PO4)3 | | Turquoise | CuOH.6[Al(OH)2].H5.(PO4)4 |
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