Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)
Category
Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.
Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)
Chalcedony Geode
Silicon Dioxide (SiO2)
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Sandstone
Arenite
Likely amber or amber-like resin fragment
Amber (fossilized plant resin), commonly succinite; identification uncertain from the image
Moss Agate
SiO2 (Cryptocrystalline Quartz)
Moss Agate
Chalcedony (SiO2) with inclusions of hornblende or chlorite
Amber
Succinite (approximate formula C10H16O)
Petrified Wood
Silicified Wood (SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Amber
Fossilized Tree Resin (Succinate)
Weathered River Rock (likely Chert or Basalt with algae)
Silicon dioxide (SiO2) with organic biofilm
Moss Agate
Silicon Dioxide (Chalcedony with green mineral inclusions), SiO2
Glauconitic Sandstone
Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Fossilized Bivalve Shell
Class Bivalvia (fossilized)
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron
Quartz Geode
Quartz (Silicon Dioxide, SiO2)
Chalcedony (Common Agate)
Silicon Dioxide (SiO2)
Shale fragment
Shale (Laminated Mudstone)
Fossilized tooth, likely a mammalian tooth fragment
Indeterminate fossil tooth; possibly an ungulate or carnivoran tooth
Coal
Coal (Sedimentary Rock / Organic Rock)
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Amber
Succinite (organic gemstone, approx. C10H16O)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Precious Coral
Corallium rubrum (Calcium carbonate with trace carotene)
Chert (Arrowhead/Artifact Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
Chert (includes Flint & Jasper)
Chert (Siliceous sedimentary rock, chemical formula SiO2)
Red Jasper
Silicon Dioxide (SiO2) with Iron Oxide inclusions
Chert with Calcite Veins
Silicon Dioxide (SiO2) with Calcium Carbonate (CaCO3) intrusions
Fossilized Dinosaur Skull (Tyrannosaurus rex)
Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica
Fancy Jasper
Jasper (Cryptocrystalline Quartz, SiO2)
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Geode (Quartz / Chalcedony Geode)
SiO2 (Silicon Dioxide)
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Sandstone (likely Fossiliferous Sandstone)
Clastic sedimentary rock (primarily SiO2)
Black Pearl (Tahitian or Irradiated Type)
Organic gemstone (Calcium Carbonate with Conchiolin Binding)
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
Shale
Shale (comprised mostly of clay minerals and quartz)
Red Sandstone
Sandstone (Quartz Arenite / Arkose with Hematite cement)
Graphite-rich metamorphic rock (graphitic schist)
Graphitic schist; chiefly graphite (C), quartz (SiO₂), and mica minerals