Rock Identifier

Category

Organic Crystal (Mineraloid)

Browse organic crystal (mineraloid) specimens identified by the Rock Identifier community.

Pink Opal (Hydrated Silica (SiO2·nH2O)) — mineral

Pink Opal

Hydrated Silica (SiO2·nH2O)

Moss Agate (Silicon Dioxide with inclusions (SiO2)) — mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2)

Moss Agate (Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Coral Rock (Coquina) (Biogenic Limestone (Calcium Carbonate - CaCO3)) — sedimentary

Coral Rock (Coquina)

Biogenic Limestone (Calcium Carbonate - CaCO3)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Limestone Pebble (Calcite-rich Sedimentary Rock (CaCO3)) — sedimentary

Limestone Pebble

Calcite-rich Sedimentary Rock (CaCO3)

Jasper (specifically a banded or dark variety) (Silicon Dioxide (SiO2) with impurities) — sedimentary

Jasper (specifically a banded or dark variety)

Silicon Dioxide (SiO2) with impurities

Chert (specifically Flint or Gray Chalcedony) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Flint or Gray Chalcedony)

Microcrystalline Quartz (SiO2)

Crinoid Stem Fragment (Crinoid (Phylum Echinodermata, Class Crinoidea)) — sedimentary

Crinoid Stem Fragment

Crinoid (Phylum Echinodermata, Class Crinoidea)

Chert (and/or Flint) (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert (and/or Flint)

Chert (Cryptocrystalline variety of Quartz, SiO2)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Chert (Green variety) (Microcrystalline Opaline/Quartz (SiO2)) — sedimentary

Chert (Green variety)

Microcrystalline Opaline/Quartz (SiO2)

Chert (often called Flint in archaeological contexts) (Silicon Dioxide (SiO2)) — sedimentary

Chert (often called Flint in archaeological contexts)

Silicon Dioxide (SiO2)

Chert (Nodule) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert Nodule (Chert (Cryptocrystalline variety of Quartz, SiO2)) — sedimentary

Chert Nodule

Chert (Cryptocrystalline variety of Quartz, SiO2)

Chert (Jasper variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert (White Chert/Flint) (Chert (SiO2)) — sedimentary

Chert (White Chert/Flint)

Chert (SiO2)

Ammonite Fossil (Small Pyritized or Calcitized Internal Mold) (Ammonoidea) — sedimentary

Ammonite Fossil (Small Pyritized or Calcitized Internal Mold)

Ammonoidea

Favosites Fossil (Honeycomb Coral) (Favosites (Extinct genus of Tabulate Coral)) — sedimentary

Favosites Fossil (Honeycomb Coral)

Favosites (Extinct genus of Tabulate Coral)

Chert (specifically Flint or Common Chert) (Silicon Dioxide (SiO2)) — sedimentary

Chert (specifically Flint or Common Chert)

Silicon Dioxide (SiO2)

Chert (Brecciated River Cobble) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Brecciated River Cobble)

Silicon Dioxide (SiO2)

Chert (Pebble) (Microcrystalline silica (SiO2)) — sedimentary

Chert (Pebble)

Microcrystalline silica (SiO2)

Chert (and Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (and Flint)

Silicon Dioxide (SiO2)

Chert (variations include Flint) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (variations include Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Moss Agate (Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron) — mineral

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions of Chlorite, Manganese, or Iron

Rounded brown sandstone or weathered river cobble (Likely quartz-rich sandstone; exact identification requires a fresh surface and tests) — sedimentary

Rounded brown sandstone or weathered river cobble

Likely quartz-rich sandstone; exact identification requires a fresh surface and tests

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Quartzite with inclusions (Quartzite) — metamorphic

Quartzite with inclusions

Quartzite

Pyrite in Shale (Iron Disulfide (FeS2) in Argillaceous Shale) — sedimentary

Pyrite in Shale

Iron Disulfide (FeS2) in Argillaceous Shale

Petrified Wood (Silicified Wood (Permineralized organic matter, głównie $SiO_2$)) — fossil

Petrified Wood

Silicified Wood (Permineralized organic matter, głównie $SiO_2$)

Petrified Wood (Silicified wood (Quartz/Chalcedony - SiO2)) — mineral

Petrified Wood

Silicified wood (Quartz/Chalcedony - SiO2)

Jasper-Agate (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Jasper-Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (Jasper/Flint Pebble) (Microcrystalline quartz (SiO2)) — sedimentary

Chert (Jasper/Flint Pebble)

Microcrystalline quartz (SiO2)

Chert (often called Flint when dark) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert / Jasper / Agate (Chalcedony Group) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert / Jasper / Agate (Chalcedony Group)

Microcrystalline Quartz (SiO2)

Moss Agate (Silicon Dioxide with inclusions (SiO2 + Mn/Fe oxides)) — mineral

Moss Agate

Silicon Dioxide with inclusions (SiO2 + Mn/Fe oxides)

Chert (Nodule) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

Travertine (Calcareous Tufa (CaCO3)) — sedimentary

Travertine

Calcareous Tufa (CaCO3)

Green Jasper (Silicon Dioxide (SiO2) with impurities of iron(II) silicate) — sedimentary

Green Jasper

Silicon Dioxide (SiO2) with impurities of iron(II) silicate

Chert (Chalcedony/Agate) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)