Rock Identifier

Category

Organic Gemstone (Not A Rock Or Mineral)

Browse organic gemstone (not a rock or mineral) specimens identified by the Rock Identifier community.

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

sedimentary
Fossilized Crinoid Stem Segment (Crinoid (Phylum Echinodermata, Class Crinoidea)) — sedimentary

Fossilized Crinoid Stem Segment

Crinoid (Phylum Echinodermata, Class Crinoidea)

sedimentary
Moss Agate (Chalcedony (Silicon Dioxide with inclusions) - SiO2) — mineral

Moss Agate

Chalcedony (Silicon Dioxide with inclusions) - SiO2

mineral
Prehnite (Prehnite (Ca2Al2Si3O10(OH)2)) — mineral

Prehnite

Prehnite (Ca2Al2Si3O10(OH)2)

mineral
Vesicular Basalt with Epidote (Vesicular Basalt (Mg, Fe)2SiO4 with Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))) — igneous

Vesicular Basalt with Epidote

Vesicular Basalt (Mg, Fe)2SiO4 with Epidote (Ca2(Al2,Fe)(SiO4)(Si2O7)O(OH))

igneous
Diorite (Diorite (Intermediate intrusive igneous rock)) — igneous

Diorite

Diorite (Intermediate intrusive igneous rock)

igneous
Agate Geode (Silicon Dioxide (SiO2)) — mineral

Agate Geode

Silicon Dioxide (SiO2)

mineral
Bauxite (Bauxite (Mixture of Hydrous Aluminum Oxides)) — sedimentary

Bauxite

Bauxite (Mixture of Hydrous Aluminum Oxides)

sedimentary
Peridot (Olivine (Mg, Fe)2SiO4) — Mineral

Peridot

Olivine (Mg, Fe)2SiO4

Mineral
Chert (Red Jasper variant) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Red Jasper variant)

Microcrystalline Quartz (SiO2)

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

Chert (Nodule)

Silicon Dioxide (SiO2)

sedimentary
Greenstone / Chert (Cryptocrystalline Quartz (SiO2) or Altered Basalt) — sedimentary or metamorphic

Greenstone / Chert

Cryptocrystalline Quartz (SiO2) or Altered Basalt

sedimentary or metamorphic
Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

sedimentary
Feldspar (Orthoclase) (Orthoclase Feldspar (KAlSi3O8)) — mineral

Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

mineral
Septarian Nodule or Mud Crack Fossil (Septarian Nodule (Concretion)) — sedimentary

Septarian Nodule or Mud Crack Fossil

Septarian Nodule (Concretion)

sedimentary
Fossilized Shark Tooth (Scapanorhynchus (Sand Tiger Shark relative)) — sedimentary

Fossilized Shark Tooth

Scapanorhynchus (Sand Tiger Shark relative)

sedimentary
Sandstone (River Rock) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (River Rock)

Arenite (composed primarily of SiO2)

sedimentary
Sandstone (Arenite (SiO2 principal)) — sedimentary

Sandstone

Arenite (SiO2 principal)

sedimentary
Turquoise (with Hematite) (CuAl6(PO4)4(OH)8·4H2O) — mineral

Turquoise (with Hematite)

CuAl6(PO4)4(OH)8·4H2O

mineral
Not a rock (Not a rock) — Not a rock

Not a rock

Not a rock

Not a rock
Not a rock (Not a rock) — Not a rock

Not a rock

Not a rock

Not a rock
Basalt (Basalt (Mafic Extrusive Igneous Rock)) — igneous

Basalt

Basalt (Mafic Extrusive Igneous Rock)

igneous
Basalt (Amygdaloidal) (Amygdaloidal Basalt) — igneous

Basalt (Amygdaloidal)

Amygdaloidal Basalt

igneous
Sandstone (Iron-stained) (Arenite (composed primarily of SiO2 with Fe2O3 staining)) — sedimentary

Sandstone (Iron-stained)

Arenite (composed primarily of SiO2 with Fe2O3 staining)

sedimentary
Banded Rock (likely Quartz-rich) (Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals) — Mineral

Banded Rock (likely Quartz-rich)

Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals

Mineral
Obsidian (Obsidian (principally SiO2 + MgO, Fe3O4)) — igneous

Obsidian

Obsidian (principally SiO2 + MgO, Fe3O4)

igneous
Almandine Garnet in Matrix (Almandine, Fe3Al2(SiO4)3) — metamorphic

Almandine Garnet in Matrix

Almandine, Fe3Al2(SiO4)3

metamorphic
Agate Geode with Quartz Druzy (Chalcedony (SiO2) and Quartz (SiO2)) — mineral

Agate Geode with Quartz Druzy

Chalcedony (SiO2) and Quartz (SiO2)

mineral
Vesicular Basalt with Quartz/Chalcedony (Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)) — igneous

Vesicular Basalt with Quartz/Chalcedony

Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)

igneous
Jasper (Red) (Silicon Dioxide (SiO2)) — sedimentary

Jasper (Red)

Silicon Dioxide (SiO2)

sedimentary
Chert (Yellow Jasper/Flint) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

sedimentary
Chert (often called Flint in this context) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint in this context)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

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

Chert (Jasper variety)

Silicon Dioxide (SiO2)

sedimentary
Milky Quartz with Iron Staining (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

mineral
Quartz Geode (Silicon Dioxide (SiO2)) — mineral

Quartz Geode

Silicon Dioxide (SiO2)

mineral
Amygdaloidal Basalt (Basalt with Secondary Mineral Infillings) — igneous

Amygdaloidal Basalt

Basalt with Secondary Mineral Infillings

igneous
Muscovite Mica (Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2) — Mineral

Muscovite Mica

Muscovite (Potassium Mica) KAl2(AlSi3O10)(OH)2

Mineral
Amethyst (Silicon Dioxide (SiO2) with iron impurities) — mineral

Amethyst

Silicon Dioxide (SiO2) with iron impurities

mineral
Sandstone (Ferruginous) (Arenite (SiO2 with iron oxide impurities)) — sedimentary

Sandstone (Ferruginous)

Arenite (SiO2 with iron oxide impurities)

sedimentary
Sandstone (Arenite (SiO2 predominantly)) — sedimentary

Sandstone

Arenite (SiO2 predominantly)

sedimentary
Shale (Shale (Lutite)) — sedimentary

Shale

Shale (Lutite)

sedimentary
Pearl (Calcium Carbonate (Aragonite or Calcite) and Conchiolin) — Mineraloid

Pearl

Calcium Carbonate (Aragonite or Calcite) and Conchiolin

Mineraloid