Chert (Jasper/Flint variety)
Microcrystalline silicon dioxide (SiO2)
Category
Browse organic (often found by beachcombers) specimens identified by the Rock Identifier community.
Chert (Jasper/Flint variety)
Microcrystalline silicon dioxide (SiO2)
Chert (Chalky variety)
Microcrystalline Quartz (SiO2)
Chert (White Chert / Flint)
Microcrystalline or Cryptocrystalline Silicon Dioxide (SiO2)
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Green Chert
Microcrystalline Quartz (SiO2)
Chert (White Chert/Flint)
Chert (SiO2)
Chert Arrowhead (Projectile Point)
Microcrystalline Quartz (SiO2)
Fossilized Shark Tooth (Otodus)
Otodus sp. (calcium phosphate/hydroxylellite)
Amber
Succinite (specific to Baltic amber), fossilized tree resin
Petrified Wood
Silicified Wood (primarily SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Fossiliferous Chert
Silicon Dioxide (SiO2) with fossil inclusions
Anthracite Coal
Anthracite
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
Crinoid Fossil in Limestone
Crinoid (Class Crinoidea) in Fossiliferous Limestone (CaCO3)
Chert (specifically Flint or Common Chert)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert / Flint
Chert (SiO2)
Chert (variations include Flint)
Chert (Silicon Dioxide, SiO2)
Chert (River Pebble)
Microcrystalline Quartz (SiO2)
Chert / Chalcedony (Agatized)
Silicon dioxide (SiO2)
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Shale (or Mudstone)
Siltstone/Argillite (composed mainly of clay and silt-sized particles)
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
Chert (Jasper/Mudstone variety with Oxidation)
Silicon dioxide (SiO2)
Moss Agate and Hematite
Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)
Amber (Green variation)
Succinite
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Hornblende inclusions
Chert (Nodule)
Silicon Dioxide (SiO2)
Chert (Black Chert or Flint)
Silicon Dioxide (SiO2)
Ironstone Concretion (Limonite/Goethite)
Iron oxide concretion (contains FeO(OH)·nH2O)
Petrified Wood
Silicified wood (Quartz/Chalcedony/Opal replacing organic matter)
Concretion
Septarian Concretion (Fragmentary)
Aragonite (Star Cluster or Twinned variety)
Aragonite (Calcium Carbonate, CaCO3)
Coal (most likely Bituminous or Anthracite)
Coal (organic sedimentary rock)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (Flint)
Chert (SiO2)
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
Chert / Flint
Chert (Cryptocrystalline Quartz, SiO2)
Black Pearl (Tahitian-style Cultured Pearl)
Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)
Chert (with Limestone/Carbonate matrix)
Sedimentary cryptocrystalline silica (SiO2)
Banded Chert (Flint)
Silicon Dioxide (SiO2)
Yellow Jasper
Silicon Dioxide (SiO2)