Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Category
Browse organic gemstone (sedimentary classification) specimens identified by the Rock Identifier community.
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Fish Fossil in Limestone
Lycoptera (likely) in Micritic Limestone
Banded Chert
Cryptocrystalline Quartz (SiO2)
Amber
Succinite (Organic Mineraloid)
Fossil Shark Tooth
Carcharodon sp. (likely Otodus or similar Lamniformes order)
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Moss Agate
Silicon Dioxide (SiO2) with inclusions
Amber
Succinite (a variety of fossilized tree resin); chemical formula appx. C10H16O
Chalcedony (Common Opal variant)
Silicon dioxide (SiO2) with varying levels of hydration
Chert (or Chalcedony)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline silica (SiO2)
Pyrite (Fool's Gold) Cube
Iron Sulfide (FeS2)
Flint (Chert)
Silicon Dioxide (SiO2)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron
Amber
Succinite (C10H16O)
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
Amber (Copal)
Organic gemstone, fossilized tree resin (often immature amber or copal)
Petrified Wood
Silicified Wood (SiO2 - Quartz/Chalcendony replacing organic matter)
Knightia Fossil in Limestone
Knightia eocaena in micritic limestone
Limestone (River Pebble)
Calcium Carbonate (CaCO3)
Shale or Slaty Mudstone
Argillaceous sedimentary rock
Pyrite Geode
Iron Disulfide (FeS2)
Black Pearl (Tahitian Type)
Aragonite / Pinctada margaritifera (CaCO3 + Conchiolin)
Geode (Unopened)
Silica-rich concretion (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
Pearl (likely Freshwater or Akoya Cultured)
Aragonite / Conchiolin composite (CaCO3)
Amber in Matrix
Succinite (Carbon-based organic polymer)
Fossiliferous Limestone with Rugose Coral
Lithostrotionella (Limestone Matrix - CaCO3)
Manganese-coated Sandstone
Clastic sedimentary rock with Manganese Oxide (often Pyrolusite or Psilomelane)
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
Coal (Bituminous or Anthracite)
Carbonaceous sedimentary rock (primarily Carbon, C)
Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)
Dyed Pink Quartzite (Jadeite Simulant)
Silicon Dioxide (SiO2) with organic dye
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
Chert
Silicon dioxide (SiO2)
Chert (specifically Flint or Common Opal)
Silicon Dioxide (SiO2)
Chert (and Fossilized Brachiopod shell)
Sedimentary Cryptocrystalline Quartz (SiO2)
Amber
Succinite (specific to Baltic amber), fossilized tree resin