Pink Opal
Hydrated silica (SiO2 "n H2O)
Category
Browse organic gemstone (not a rock) specimens identified by the Rock Identifier community.
Pink Opal
Hydrated silica (SiO2 "n H2O)
Shale or Slaty Mudstone
Argillaceous sedimentary rock
Jasper (Iron-stained Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Fossil Shell
Brachiopod or Mollusk fossil
Fossilized coral (likely honeycomb or branching coral)
Fossil coral; probable Scleractinia or Tabulata, composition mainly microcrystalline CaCO₃
Moss Agate
Silicon Dioxide (Chalcedony variety) with green hornblende or chlorite inclusions - SiO2
Limestone with Fossil Fragment
Sedimentary carbonate rock (CaCO3)
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
Amber
Succinite (fossilized organic resin)
Jasper
Silicon Dioxide (SiO2) with impurities
Gravel / Limestone Fragment
Calcium Carbonate (CaCO3) / Fine-grained Sedimentary Rock
Jasper
Silicon Dioxide (SiO2) with iron oxide impurities
Limestone with Calcite Veining
Sedimentary Rock (Calcium Carbonate, CaCO3)
Heart-shaped Limestone
Calcium Carbonate (CaCO3)
Jasper
Jasper (Silicon Dioxide, SiO2)
Coal
Bituminous Coal / Anthracite
Chert Nodule / Ironstone Concretion
Microcrystalline Quartz (SiO2) with Iron Oxides
Microcrystalline Quartz (Chert/Agate)
Silicon Dioxide (SiO2)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Chert (Yellow Jasper/Flint)
Microcrystalline Quartz (SiO2)
River Cobble (Sandstone)
Arenite (primarily SiO2)
Limestone with Iron Oxide Staining
Sedimentary Rock (Calcite, CaCO3)
Ironstone Nodules in Chalk/Limestone
Limonite/Goethite concretions (FeO(OH)·nH2O) in Calcium Carbonate matrix (CaCO3)
Chert (Flint)
Silicon Dioxide (SiO2)
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
Fossiliferous Rock (Invertebrate Fossil in Matrix)
Fossiliferous limestone or shaly matrix containing skeletal fossil remains
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Geode with Quartz Crystal Cavity
Silicon Dioxide (SiO2) in Calcareous/Siliceous Matrix
Fire Opal
Hydrated Silica (SiO2·nH2O)
Glauconitic Sandstone
Glauconitic Sandstone with high Glauconite concentration ((K,Na)(Fe3+,Al,Mg)2(Si,Al)4O10(OH)2)
Fossilized Brachiopod
Brachiopoda (Phylum)
Chert (Flint Nodules)
Silicon Dioxide (SiO2)
Jasper
Microcrystalline Quartz (SiO2)
Seashell Fossil
Gastropoda fossil
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Shale
Shale (Fine-grained clastic sedimentary rock)
Starfish Fossil
Asteroidea fossil
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
Amber
Fossilized Tree Resin
Amber
Succiniferous fossil resin (C10H16O)