Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Category
Browse organic gemstone specimens identified by the Rock Identifier community.
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Labradorite
Feldspar (variety of Anorthite), (Ca,Na)(Al,Si)4O8
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3)
Sodalite
Na8(Al6Si6O24)Cl2
Quartz (Milky or Smoky Quartz)
Silicon Dioxide (SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2) with Goethite/Iron oxide inclusions
Hypersthene
Enstatite (Hypersthene variety), (Mg,Fe)SiO3
Clear Quartz
Silicon Dioxide (SiO2)
Red Tiger's Eye
Silicified Crocidolite (Quartz pseudo-morph after Crocidolite), SiO2
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Citrine
Silicon Dioxide (SiO2) with iron impurities
Yellow Calcite
Calcium Carbonate (CaCO3)
Jasper
Jasper (Silicon Dioxide, SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Quartz (Milky/Common)
Silicon Dioxide (SiO2)
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
Fuchsite Quartzite (Green Quartzite)
Fuchsite-bearing Quartzite (K(Al,Cr)2(AlSi3O10)(OH)2 + SiO2)
Tiger's Eye
Tiger's eye (Pseudomorph of Quartz after Crocidolite), SiO2
Amethyst (Purple), Sulfur (Yellow), and Blue Apatite
SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)
Quartz (Druzy/Macro-crystalline)
Silicon Dioxide (SiO2)
Labradorite (Dark or Black variety)
Labradorite (member of Plagioclase Feldspar group), (Na,Ca)(Si,Al)4O8
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Chrysocolla in Cuprite (Sonoran Sunrise)
Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O) (Chrysocolla) and Cu2O (Cuprite)
Diorite (Dalmatian Stone)
Phaneritic Plutonic Diorite
Olivine (Peridotite)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
Chrysoprase
Chalcedony (cryptocrystalline silica containing nickel); Chemical Formula: SiO2 with Ni impurities
Amethyst
Silicon dioxide (variant with ferric iron impurities), SiO2
Blue Lace Agate
Chalcedony (SiO2) with trace impurities
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
Amazonite
Microcline (variety Amazonite) - K(AlSi3O8)
Red Jasper
Silicon Dioxide with Hematite (SiO2 + Fe2O3)
Quartz (Chatoyant or Milky variety)
Silicon Dioxide (SiO2)
Unakite
Unakite (Metasomatized Granodiorite)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)
Quartz (Milky/Smoky variety)
Silicon Dioxide (SiO2)
Yellow Aventurine
Quartz (Silicon Dioxide) with Mica inclusions (SiO2)
Red Tiger's Eye
Pseudomorph of Macrocrystalline Quartz after Crocidolite (SiO2)
Green Quartzite
Metamorphic Quartz (SiO2) with Chromium-rich inclusions (Fuchsite)
Tumbled Moonstone
Feldspar (Orthoclase/Albite), KAlSi3O8