Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Sandstone (Quartzose)
Arenite (primarily SiO2)
Serpentinite (often called Jade or Nephrite substitute)
Serpentinite (composed primarily of Antigorite, Lizardite, or Chrysotile)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxide (Limonite/Hematite) coating
Jasper with Quartz Vein
Silicon Dioxide (SiO2) with impurities
Chert (vuggy variety)
Microcrystalline silica (SiO2)
Amber
Succinite (a Fossilized Tree Resin); Chemical formula is approximately C10H16O
Quartz Geode/Druzy Quartz
Quartz (SiO₂)
Amazonite
Microcline (KAlSi3O8) with Pb impurities
Sunstone
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8
Amethyst
Quartz (Silicon Dioxide with Iron impurities), SiO2
Amazonite
KAlSi3O8 (Potassium aluminum silicate - blue-green variety of Microcline)
Amazonite
Potassium Aluminum Silicate (KAlSi3O8)
Amazonite
K(AlSi3O8) - Potassium Aluminum Silicate
Amazonite
KAlSi3O8 (Potassium Aluminum Silicate)
Sunstone
Oligoclase (Plagioclase Feldspar) - (Ca,Na)(Al,Si)4O8 with Hematite or Copper inclusions
Sunstone
Plagioclase Feldspar (containing (Ca,Na)(Al,Si)4O8 with Hematite or Copper inclusions)
Citrine
Silicon Dioxide (SiO2)
Amazonite
Potassium Feldspar (Microcline), K(AlSi3O8)
Quartz / Citrine Quartz
Silicon Dioxide (SiO2)
Amazonite
Amazonite (KAlSi3O8)
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Amethyst
Silicon dioxide / Quartz (SiO2+Fe4+)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Amethyst
Amethyst (Silicon Dioxide, SiO2 with Iron impurities)
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Sandstone (Glacial Cobble)
Arenite / Sedimentary Rock (primarily SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Not a rock
Not a rock
Chert (specifically Blue Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Amber with Inclusion
Succiniferous fossil resin (C10H16O)
Amber
Succinate (Fossilized Tree Resin)
Jasper
Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (specifically Yellow/Honey Jasper variety)
Cryptocrystalline Quartz (SiO2)
Carnelian
Carnelian (a variety of Chalcedony, SiO ₂)
Citrine
Silicon dioxide (SiO2) - yellow quartz variety
Quartz (likely tumbled or naturally water-worn)
Quartz (SiO₂ - Silicon Dioxide)
Chert (Jasper/Flint variety)
Microcrystalline quartz (SiO2)
Ironstone Concretion / Limonite Node
Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)
Manganese Oxide Crust on Limestone
Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3