Rock Identifier

Category

Organic Gemstone (Often Associated With Sedimentary Sequences)

Browse organic gemstone (often associated with sedimentary sequences) specimens identified by the Rock Identifier community.

Stromatolite (Biogenic Sedimentary Rock (composed predominantly of CaCO3)) — sedimentary

Stromatolite

Biogenic Sedimentary Rock (composed predominantly of CaCO3)

Moss Agate (Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite) — mineral

Moss Agate

Silicon Dioxide (SiO2) with inclusions of hornblende or chlorite

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)

Granodiorite (Phaneritic Granodiorite) — igneous

Granodiorite

Phaneritic Granodiorite

Chert (Flint variety) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (Flint variety)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Chert (Gravel)

Microcrystalline silica (SiO2)

Chert (Iron-rich) (Silicon Dioxide (SiO2) with Hematite (Fe2O3)) — sedimentary

Chert (Iron-rich)

Silicon Dioxide (SiO2) with Hematite (Fe2O3)

Chert (Jasper/Flint variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Chert with Iron Staining (Microcrystalline Quartz (SiO2)) — sedimentary

Chert with Iron Staining

Microcrystalline Quartz (SiO2)

Coquina or Fossiliferous Limestone (Fossiliferous Calcarenite (CaCO3)) — sedimentary

Coquina or Fossiliferous Limestone

Fossiliferous Calcarenite (CaCO3)

Chert (and Jasper pebble) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (and Jasper pebble)

Microcrystalline Silica (SiO2)

Chalcedony (Chalcedony (SiO₂)) — Mineral

Chalcedony

Chalcedony (SiO₂)

Hypersthene (Hypersthene ((Mg,Fe)SiO3)) — mineral

Hypersthene

Hypersthene ((Mg,Fe)SiO3)

Porphyry (Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)) — igneous

Porphyry

Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)

Chert (Jasper/Flint variation) (Chert (SiO2)) — sedimentary

Chert (Jasper/Flint variation)

Chert (SiO2)

Agate (Grey Agate Slice) (Microcrystalline Quartz (SiO2)) — mineral

Agate (Grey Agate Slice)

Microcrystalline Quartz (SiO2)

Quartz (Milky/Clear variety) (Silicon Dioxide (SiO2)) — mineral

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Chert / River Pebble (Silicon Dioxide (SiO2)) — sedimentary

Chert / River Pebble

Silicon Dioxide (SiO2)

Quartz (Quartz (SiO₂)) — Mineral

Quartz

Quartz (SiO₂)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Chert (Tan/Grey variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Tan/Grey variety)

Silicon Dioxide (SiO2)

Jasper River Pebble (Silicon Dioxide (SiO2)) — sedimentary (microcrystalline quartz)

Jasper River Pebble

Silicon Dioxide (SiO2)

sedimentary (microcrystalline quartz)

Serpentinite (Serpentinite (composed primarily of Serpentine group minerals, e.g., Antigorite, Lizardite, Chrysotile)) — metamorphic

Serpentinite

Serpentinite (composed primarily of Serpentine group minerals, e.g., Antigorite, Lizardite, Chrysotile)

Pink Opal (Hydrated silicon dioxide (SiO2·nH2O) with inclusions) — mineral

Pink Opal

Hydrated silicon dioxide (SiO2·nH2O) with inclusions

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

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

Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions

Granodiorite (Granodiorite (Quartz-Feldspar-Biotite Plutonic Rock)) — igneous

Granodiorite

Granodiorite (Quartz-Feldspar-Biotite Plutonic Rock)

Green Aventurine (Silicon Dioxide (SiO2) with inclusions of Fuchsite) — Mineral

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite

Quartz / Chert (Silicon Dioxide (SiO2)) — Mineral / Sedimentary

Quartz / Chert

Silicon Dioxide (SiO2)

Mineral / Sedimentary

Almandine Garnet (Almandite (Fe3Al2(SiO4)3)) — Mineral

Almandine Garnet

Almandite (Fe3Al2(SiO4)3)

Fossil Shark Tooth (Cretaceous white shark type) (Squalicorax (commonly known as Crow Shark)) — Organic specimen (fossil)

Fossil Shark Tooth (Cretaceous white shark type)

Squalicorax (commonly known as Crow Shark)

Organic specimen (fossil)

Jasper (Chert (Silica: SiO2)) — sedimentary

Jasper

Chert (Silica: SiO2)

Basalt (Mafic Igneous Rock (primarily Plagioclase and Pyroxene)) — igneous

Basalt

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Red Dyed Howlite (Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)) — mineral

Red Dyed Howlite

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Diorite (Salt and Pepper Rock) (Diorite (comprising Plagioclase Feldspar, Hornblende, and Biotite)) — igneous

Diorite (Salt and Pepper Rock)

Diorite (comprising Plagioclase Feldspar, Hornblende, and Biotite)

Scoria (Extrusive Igneous Rock (Basaltic/Andesitic Composition)) — igneous

Scoria

Extrusive Igneous Rock (Basaltic/Andesitic Composition)

Agate (various color varieties) (SiO₂ (Silicon Dioxide)) — Mineral (specifically a variety of Chalcedony, which is a microcrystalline quartz)

Agate (various color varieties)

SiO₂ (Silicon Dioxide)

Mineral (specifically a variety of Chalcedony, which is a microcrystalline quartz)

Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.) (Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)) — mineral

Mixed Tumbled Gemstones (Agate, Aventurine, Pyrite, etc.)

Multiple (principally Silicon Dioxide SiO2 and Iron Disulfide FeS2)

Calligraphy Stone (Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)) — sedimentary

Calligraphy Stone

Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)

Green Moss Agate / Jasper (Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions) — sedimentary

Green Moss Agate / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron and Manganese inclusions

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Rhodonite (Rhodonite (MnSiO3)) — mineral

Rhodonite

Rhodonite (MnSiO3)