Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Sunstone
Plagioclase Feldspar (containing (Ca,Na)(Al,Si)4O8 with Hematite or Copper inclusions)
Diamond
Diamond (C)
Citrine
Silicon Dioxide (SiO2)
Quartz (Grain)
Silicon Dioxide (SiO2)
Amethyst
Silicon dioxide (SiO2) with iron impurities
Banded Chert
Cryptocrystalline Quartz (SiO2)
Milky Quartz with Mineral Inclusions
Silicon Dioxide (SiO2)
Garnet
Garnet Group (Silicate Minerals), formula varies e.g., Alm: Fe3Al2(SiO4)3
Quartz
Silicon Dioxide (SiO2)
Olivine
(Mg, Fe)2SiO4
Sandstone (Quartzose Sandstone)
Arenite (primarily SiO2)
Chert (Flint/Jasper variety)
Silicon Dioxide (SiO2)
Schist
Mica Schist
Septarian Nodule (Dragon Stone)
Septarian Concretion (CaCO3 with Siderite and Calcite)
Quartz (Clear Quartz)
Silicon Dioxide (SiO2)
Amazonite
Microcline (KAlSi3O8) with Pb impurities
Quartz Pebble
Silicon Dioxide (SiO2)
Orange Quartz (Citrine Quartz)
Silicon Dioxide (SiO2) with iron impurities
Amazonite
KAlSi3O8 (Potassium Aluminum Silicate)
Green Aventurine
Aventurine Quartz (SiO2 with inclusions of Fuchsite mica)
Milky Quartz
Silicon Dioxide (SiO2)
Chalcedony
Cryptocrystalline Quartz (SiO2)
Turquoise
CuAl6(PO4)4(OH)8·4H2O
Slag (Industrial By-product)
Anthropogenic Vitreous Silica/Iron Silicate
Fossil Coral (Favosites)
Favosites (Order: Tabulata, Phylum: Cnidaria)
Variscite in Matrix
Variscite (AlPO4 · 2H2O)
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
Lepidolite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
Yellow Diamond (Faceted)
Diamond (pure carbon) with nitrogen impurities, C
Ocean Jasper Mushroom
Orbicular Jasper (Silicon Dioxide, SiO2 mixed with various impurities)
Emerald
Beryl (Be3Al2(SiO3)6) with trace Chromium/Vanadium
Cubic Zirconia (Diamond Simulant)
Zirconium Dioxide (ZrO2)
Blue Lace Agate
Banded Chalcedony (SiO2)
Yellow Chert or Jasper
Silicon Dioxide (SiO2)
Milky Quartz
Crystalline Silicon Dioxide (SiO2)
Ocean Jasper
Silicon Dioxide (SiO2)
Siltstone
Siltstone (primarily composed of silica and clay minerals)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Amethyst
Quartz (Silicon Dioxide with Iron impurities), SiO2
Rose Quartz
SiO2 (Silicon Dioxide with trace amounts of titanium, iron, or manganese)