Chert (and Petrified Wood)
Silicon Dioxide (SiO2)
Category
Browse organic materia (not a rock or mineral) specimens identified by the Rock Identifier community.
Chert (and Petrified Wood)
Silicon Dioxide (SiO2)
Fossilized Fish Skeleton in Matrix
Vertebrata (Class: Actinopterygii), typically found in limestone or shale matrices
Green Sandstone
Glauconitic Sandstone
Chert (containing Iron Oxide)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (often called Jasper in this color variety)
Microcrystalline Quartz (SiO2)
Chert (Flint/Chalcedony)
Microcrystalline Quartz (SiO2)
Chert / Flint
Microcrystalline or cryptocrystalline quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2 - Quartz/Chalcedony replacement)
Petrified Wood
Silicified wood (Quartz, SiO2)
Pearl
Calcium Carbonate (Aragonite/Calcite mixed with Conchiolin), CaCO3
Dendritic Agate / Moss Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
Moss Agate
Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with dendritic inclusions
Pearl
Aragonite / Calcium Carbonate (CaCO3)
Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
Pyrite
Iron Sulfide (FeS2)
Sandstone with Secondary Mineral Encrustation
Arenite with Silica/Calcite deposits (SiO2 or CaCO3)
Brecciated Jasper
Silicon Dioxide (SiO2) with Hematite impurities
Glauconitic Sandstone
Glauconitic Quartz Arenite
Ironstone Concretion
Siderite or Hematite Concretion
Amber
Fossilized Tree Resin (Generic formula roughly C10H16O)
Red Sandstone
Sandstone (principally Quartz with Iron Oxide coating)
Pearl
Calcium carbonate (CaCO3) + organic conchiolin (Biogenic Mineral)
Quartz Geode (likely within Limestone or Dolomite matrix)
Quartz (SiO₂)
Petrified Wood
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Painted River Pebble (likely Basalt or Greywacke)
Aphanitic Lithic Clast with Anthropogenic Pigment coating
Unable to identify - Image contains non-geological items
Fossilized Sand Tiger Shark Tooth
Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)
Geode with Quartz and possibly Jasper/Hematite
Quartz (SiO2) and Chalcedony (cryptocrystalline SiO2), possibly stained by iron oxides
Quartz Vein in Sedimentary Matrix
Silicon Dioxide (SiO2) with host rock
Druzy Quartz on Host Rock
Silicon Dioxide (SiO2) with various iron-oxide inclusions
Basalt (Amygdaloidal)
Amygdaloidal Basalt
Chert / Jasper
Microcrystalline Quartz (SiO2)
Pink Opal
Hydrated Silica (SiO2·nH2O)
Petrified Wood
Silicified Wood (SiO2)
Petrified Wood (Silicified Wood)
Silicified fossil wood (SiO2)
Ironstone Concretion / Limonite Node
Goethite and Limonite (FeO(OH) nH2O)
Sandstone with Concretions / Liesegang Rings
Arenite with iron oxide banding
Druzy Quartz on Chert/Siltstone
Silicon Dioxide (SiO2) on Microcrystalline Silica/Siltstone matrix