Ironstone Concretion
Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)
Category
Browse mineral and organic gemstone specimens identified by the Rock Identifier community.
Ironstone Concretion
Siderite or Limonite Concretion (FeCO3 or FeO(OH)·nH2O)
Fossilized bone fragment (probable mammalian tooth or bone)
Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
Moss Agate
Silicon Dioxide (Chalcedony variety)
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Hornblende inclusions
Tree Agate
Dendritic Agate (Silicon Dioxide, SiO2)
Fossilized Bone
Permineralized Bone (Vertebrate Fossil)
Jasper
Silicon dioxide (Quartz variety), SiO2
Sandstone with Iron Oxide Concretion
Arenite with Hematite/Goethite Concretion
Weathered granitic rock
Granite or granodiorite, likely quartz–feldspar–mica aggregate
Yellow Jasper
Silicon Dioxide (SiO2) with iron inclusions
Quartz Geode
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily Quartz/Chalcedony, SiO2)
Chert (variously known as Flint)
Microcrystalline quartz (SiO2)
Fossiliferous Limestone (Coquina)
Calcite (CaCO3) with Bioclastic inclusions
Fossil Coral
Cnidaria Anthozoa (Fossilized)
Petrified Wood
Silicified Wood (SiO2)
Milky quartz (likely quartz fragment)
Quartz, silicon dioxide (SiO₂)
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
Milky quartz
Quartz (silicon dioxide, SiO₂)
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
Fossilized Shark Tooth (Otodus)
Otodus sp. (calcium phosphate/hydroxylellite)
Quartz
Silicon Dioxide (SiO2)
Chrysocolla
Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O
Quartz with Inclusions
Silicon Dioxide (SiO2)
Emerald
Beryl (Be3Al2(SiO3)6)
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
Chert (Jasper)
Microcrystalline Quartz (SiO2)
Amber
Succinite (specifically Baltic Amber) - Formula: C10H16O (approximate)
Amber
Succinite (specifically for Baltic Amber), Formula: C10H16O
Amber
Succinite (C10H16O)
Amber
Succinite (specifically for Baltic amber); approximate formula C10H16O
Fossilized Shark Tooth (Otodus)
Otodus obliquus
Fossiliferous Sandstone
Sedimentary rock containing invertebrate fossils
Quartz (Chert/Chalcedony variety)
Silicon Dioxide (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossilized Shark Tooth
Bioapatite (Calcium Hydroxyapatite) replacement
Mosasaur Tooth Fossil
Mosasaurid vertebrate fossil (Hydroxyapatite)
Pyrite
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)