Pearl
Aragonite (CaCO3 with conchiolin)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Pearl
Aragonite (CaCO3 with conchiolin)
Glauconitic Sandstone
Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Chert
Silicon dioxide (SiO2)
Red Coral
Corallium rubrum
Pyrite on Limestone
Iron Disulfide (FeS2) in Calcium Carbonate (CaCO3) matrix
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxide
Natural White Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Chert (Brecciated Chert)
Silicon Dioxide (SiO2)
Pearl
Organic gemstone (Calcium carbonate / CaCO3 + Conchiolin)
Chert (Arrowhead/Artifact Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Agate (Moss or Dendritic Agate)
Chalcedony (Silicon Dioxide, SiO2)
Pearl
Organic Mineral (CaCO3 with conchiolin)
Amber
Succinite
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Fossiliferous Shale
Laminated Mudrock with plant fossils
Jasper
Silicon dioxide (SiO2)
Amber
Succinite (C10H16O)
Chert (Nodular or Massive Variety)
Cryptocrystalline Quartz (SiO2)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Chert (variations include Flint or Jasper)
Silicon Dioxide (SiO2)
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
Amber (Copal)
Succinite (fossilized tree resin)
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Glauconitic Sandstone (Greensand)
Glauconitic Quartz Arenite (containing Glauconite, (K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
Moss Agate
Chalcedony (Silicon Dioxide - SiO2) with inclusions
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Amber
Fossilized Tree Resin (Succinate)
Shale
Fissile mudstone (primarily clay minerals and silt-sized quartz)
Moonstone
Orthoclase (Potassium Aluminum Silicate), Formula: (K,Na)AlSi3O8
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
Shale
Clastic sedimentary rock (primarily clay and silt minerals)
Amber
Succinite (C10H16O)
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (includes Flint & Jasper)
Chert (Siliceous sedimentary rock, chemical formula SiO2)