Chalcedony in Matrix (likely Agatized Coral or Chert)
Silicon Dioxide (SiO2)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Chalcedony in Matrix (likely Agatized Coral or Chert)
Silicon Dioxide (SiO2)
Bivalve Fossil in Sedimentary Matrix
Fossiliferous Mudstone (Class: Bivalvia)
Shungite
Fullerene-bearing carbonaceous rock
Calligraphy Stone
Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)
Amber (Dark/Black Variety)
Succinite (Resinite), C10H16O
Sandstone Pebble
Arenite (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Concretionary Sandstone
Clastic Sedimentary Rock (Sandstone with secondary mineral cementation)
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Jasper
Microcrystalline quartz (SiO2)
Moss Agate
Silicon Dioxide with inclusions (SiO2 + Fe/Mg/Mn/Chlorite)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
Banded Chert
Microcrystalline Quartz (SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Quartz
Silicon Dioxide (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Garnet Schist
Almandine Garnet in Schist (X3Al2(SiO4)3)
Petrified Wood
Silicified Wood (SiO2)
Quartz Druse on Basalt Matrix
Silicon Dioxide (SiO2)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
Agate (Carnelian / Chalcedony)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Yellow Quartz / Chalcedony
Silicon Dioxide (SiO2)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminum)
Malachite-bearing Rock
Cu2CO3(OH)2
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Moss Agate
Chalcedony (SiO2) with dendritic inclusions of Manganese or Iron oxide
Emerald in Host Rock
Beryl (Be3Al2Si6O18) with Chromium/Vanadium impurities
Quartz Vein / Quartzite
Silicon Dioxide (SiO2)
Quartz Geode or Vein Quartz
Silicon Dioxide (SiO2)
Quartz (Iron-Stained)
Silicon Dioxide (SiO2)
Lake Superior Agate
Banded Chalcedony (Silicon Dioxide, SiO2)
Black Pearl (Tahitian or Irradiated Type)
Organic gemstone (Calcium Carbonate with Conchiolin Binding)
Quartz
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
Orthoclase Feldspar
KAlSi3O8 (Potassium Aluminum Silicate)
Dendritic Agate
Chalcedony (SiO2) with manganese/iron oxide inclusions
Quartz
Silicon Dioxide (SiO2)
Glauconite (Green Sandstone)
Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
Agate Geode Slice (with Druzy Quartz)
Silicon Dioxide (SiO2)