Red Coral (Sponge Coral / Apple Coral)
Corallium rubrum (calcium carbonate / organic gem)
Category
Browse organic structure (not a rock) specimens identified by the Rock Identifier community.
Red Coral (Sponge Coral / Apple Coral)
Corallium rubrum (calcium carbonate / organic gem)
Shungite
Non-crystalline carbon (high-carbon metamorphic rock)
Petrified Wood
Silicified Wood (primarily Chalcedony or Quartz, SiO2)
Banded Chert (River Siltstone)
Microcrystalline Quartz (SiO2)
Ironstone Concretion / Goethite-Hematite Geode
Goethite / Hematite Concretion (Fe3O4 / FeO(OH) / Fe2O3)
Ammonite Fossil (Small Pyritized or Calcitized Internal Mold)
Ammonoidea
Green Moss Agate
Silicon Dioxide (SiO2) with Mineral Inclusions
Chert (Arrowhead/Artifact Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Chert (with Epidote/Quartz veining)
Cryptocrystalline silica (SiO2) with Epidote/Quartz inclusions
Red Jasper
Jasper (Silicon Dioxide, SiO2)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
Petrified Wood (Black / Carbonized)
Silicon Dioxide (Quartz/Chalcedony replacing Organic Matter)
Not a rock, mineral, or geological specimen
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Chert (Nodular)
Microcrystalline Silica (SiO2)
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
Limestone with Quartz/Calcite Veins
Sedimentary Limestone (CaCO3 with SiO2 or CaCO3 intrusions)
Naga Silver-Inlaid Ebony and Bone/Horn Beads
Diospyros (Ebony) or Keratin (Horn) with Silver/White-Metal Inlay
Limestone / Dolomite
Calcium Carbonate (CaCO3) / Calcium Magnesium Carbonate (CaMg(CO3)2)
Fossilized Bivalve Shell
Bivalvia (Phylum Mollusca)
Chert / Jasper
Cryptocrystalline Silica (SiO2)
Limestone
Calcium Carbonate (CaCO3) / Limestone
Moss Agate
Chalcedony (Silicon Dioxide) with dendritic inclusions (SiO2)
Chert (often called Jasper or River Siltstone)
Microcrystalline Quartz (SiO2)
Travertine (Tufa)
Chemical Sedimentary Rock / Travertine (CaCO3)
Moss Agate
Chalcedony (SiO2) with inclusions of hornblende or chlorite
Chert (Jasper variation)
Silicon Dioxide (SiO2)
Flint (Chert)
Silicon Dioxide (SiO2)
Chert (with Liesegang Banding)
Microcrystalline quartz (SiO2)
Limestone Boulder
Sedimentary Rock (Calcium Carbonate, CaCO3)
Bivalve Fossil (Fossilized Shell)
Class Bivalvia (fossilized in Calcium Carbonate/Aragonite)
Chert (Iron-stained)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Crinoid Fossil in Limestone
Crinoid (Class Crinoidea) in Fossiliferous Limestone (CaCO3)
Chert / Pink Flint
Cryptocrystalline Quartz (SiO2)
Chert (Yellow Jasper/Flint)
Silicon Dioxide (SiO2)
Metal Alloy (Likely Pewter or Sterling Silver)
Not a natural geological specimen; composed of refined metals. If pewter, it's a tin-based alloy. If sterling silver, it's 92.5% silver and 7.5% other metals (usually copper).
Petrified Wood
Silicified Wood (primarily SiO2 - Silicon Dioxide / Chalcedony)
Petrified Wood
Silicified Wood (SiO2)
Sandstone (Glauconitic)
Glauconitic Quartz Sandstone (SiO2 + (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Chert (River Siltstone/Quartzite type)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)