Pearl
Aragonite / Calcium Carbonate (CaCO3)
Category
Browse organic (mineraloid) specimens identified by the Rock Identifier community.
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Limonite (Iron Ore)
Limonite (Hydrated iron(III) oxide-hydroxide, FeO(OH)·nH2O)
Fossiliferous Chert (with Fossil Shells)
Silicon Dioxide (SiO2) with biogenic inclusions
Travertine
Calcareous Tufa / Travertine (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Tumbled brown quartz/chert pebble
Microcrystalline quartz (SiO₂), possibly chert or jasper
Tumbled amber
Amber (fossilized plant resin; commonly succinite, C10H16O)
Mixed Gemstone and Mineral Collection
Silicon Dioxide (SiO2) based minerals and others
Amber
Succinite (Fossilized Tree Resin)
Botiroidal Chalcedony or Silicified Fossil Coral
Silicon Dioxide (SiO2) - Chalcedony / Scleractinia (if fossilized)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2 with chlorite inclusions)
Petrified Wood
Silicified Wood (SiO2)
Moss Agate
Chalcedony (SiO2) with inclusions of manganese or iron oxides
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions
Petrified Wood
Silicified Wood (SiO2)
Limestone (Tufa/Travertine)
Sedimentary Calcium Carbonate (CaCO3)
Concretion
Septarian Concretion (Fragmentary)
Chert Nodules or Concretion
Cryptocrystalline Quartz (SiO2)
Chert (containing Fossil Mold)
Silicon dioxide (SiO2)
Amber (Rough Baltics/Beach Specimen)
Succinicum (Organic Gemstone - Fossilized Resin)
Amber
Succinates (fossilized tree resin), approximately C10H16O
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Moss-covered Limestone with Quartz/Calcite Pocket
Calcium Carbonate (CaCO3) rock with biological moss coating
Fossiliferous Limestone
Biogenic Limestone (CaCO3 with fossil fragments)
Fossiliferous Limestone
Biomicrite / Limestone with fossils
Limestone
Calcium Carbonate (CaCO3)
Rounded brown sandstone or weathered river cobble
Likely quartz-rich sandstone; exact identification requires a fresh surface and tests
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
Amber
Fossilized Tree Resin (C10H16O)
Sandstone with Iron Oxide Concretion
Arenite with Hematite/Goethite Concretion
Amber
Fossilized Tree Resin
Amber
Succinite (Fossilized Tree Resin, C10H16O)
Amber
Succinite (C10H16O)
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
Green Moss Agate / Jasper
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
Calligraphy Stone
Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)
Shale
Shale (comprised mostly of clay minerals and quartz)