Rock Identifier

Category

Biogenic Material

Browse biogenic material specimens identified by the Rock Identifier community.

Learn about Biogenic Material in the encyclopedia

Peat

Diatomite

Dunite

Limonite

Diamond

Peacock Opal

Metarhyolite

Rhodochrosite

Shell Opal

Madagascar Opal

Lavender Obsidian

Electric Blue Obsidian

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Quartz vein in Host Rock (Crystalline Silicon Dioxide (SiO2) in Lithic Matrix) — metamorphic

Quartz vein in Host Rock

Crystalline Silicon Dioxide (SiO2) in Lithic Matrix

Basalt Pebble (Mafic Igneous Rock (Basalt)) — igneous

Basalt Pebble

Mafic Igneous Rock (Basalt)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Rough Diamond (Diamond (pure carbon, C)) — mineral

Rough Diamond

Diamond (pure carbon, C)

Weathered granite or granitic pegmatite cobble (Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals) — igneous

Weathered granite or granitic pegmatite cobble

Granite/granitic rock, composed mainly of quartz (SiO₂), feldspar, and minor biotite or other dark minerals; the reddish-brown areas may be iron-oxide staining or weathered accessory minerals

Quartzite pebble (Quartzite) — metamorphic

Quartzite pebble

Quartzite

Tumbled citrine quartz (likely heat-treated amethyst) (Quartz, SiO₂; crystalline variety citrine) — mineral

Tumbled citrine quartz (likely heat-treated amethyst)

Quartz, SiO₂; crystalline variety citrine

Gravel and Pavement Aggregates (Unconsolidated rock fragments / detrital sediments) — sedimentary

Gravel and Pavement Aggregates

Unconsolidated rock fragments / detrital sediments

Chrysocolla in Chalcedony (Gem Silica) (Hydrated copper phyllosilicate and silicon dioxide (SiO2 with (Cu,Al)2H2Si2O5(OH)4)) — mineral

Chrysocolla in Chalcedony (Gem Silica)

Hydrated copper phyllosilicate and silicon dioxide (SiO2 with (Cu,Al)2H2Si2O5(OH)4)

Sandstone (Sedimentary Arenite) — sedimentary

Sandstone

Sedimentary Arenite

Laterite Gravel with Quartz (Ferruginous Laterite (Fe2O3·nH2O)) — sedimentary

Laterite Gravel with Quartz

Ferruginous Laterite (Fe2O3·nH2O)

Quartzite (Metamorphosed Quartz Sandstone (SiO2)) — metamorphic

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Basalt (Phaneritic or Diabase) (Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)) — igneous

Basalt (Phaneritic or Diabase)

Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)

River Cobble (Clastic Sedimentary (Quartz-rich Cobble)) — sedimentary

River Cobble

Clastic Sedimentary (Quartz-rich Cobble)

Granite (Granite) — igneous

Granite

Granite

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Basalt (Basalt (Ma-Fe Silicate)) — igneous

Basalt

Basalt (Ma-Fe Silicate)

Quartzite Pebble (Quartzite (SiO2)) — metamorphic

Quartzite Pebble

Quartzite (SiO2)

Quartzite (Quartzite (mostly SiO2)) — metamorphic

Quartzite

Quartzite (mostly SiO2)

Basalt (Basalt (Aphanitic Mafic Volcanic Rock)) — igneous

Basalt

Basalt (Aphanitic Mafic Volcanic Rock)

Quartzite (River Pebble) (Metamorphosed Quartz-rich Sandstone (SiO2)) — metamorphic

Quartzite (River Pebble)

Metamorphosed Quartz-rich Sandstone (SiO2)

Basalt (Basalt (Mafic Extrusive Igneous Rock)) — igneous

Basalt

Basalt (Mafic Extrusive Igneous Rock)

Quartzite Pebbles (Meta-quartzite (SiO2)) — metamorphic

Quartzite Pebbles

Meta-quartzite (SiO2)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Basalt (Basalt) — igneous

Basalt

Basalt

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Granite Cobble (Felsic Intrusive Igneous Rock) — igneous

Granite Cobble

Felsic Intrusive Igneous Rock

Basalt (Vesicular/Scoria) (Vesicular Basalt) — igneous

Basalt (Vesicular/Scoria)

Vesicular Basalt

Granodiorite (Granodiorite (Na,Ca)(Al,Si)4O8) — igneous

Granodiorite

Granodiorite (Na,Ca)(Al,Si)4O8

Basalt (Basalt (Aphanitic Mafic Igneous Rock)) — igneous

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Quartz Sand/Gravel (Silicon Dioxide (SiO2)) — sedimentary

Quartz Sand/Gravel

Silicon Dioxide (SiO2)

Tumbled blue-gray stone, likely quartzite or fine-grained basalt (Provisional identification: quartzite (mostly quartz, SiO₂) or basalt (plagioclase–pyroxene); image alone cannot distinguish reliably) — igneous

Tumbled blue-gray stone, likely quartzite or fine-grained basalt

Provisional identification: quartzite (mostly quartz, SiO₂) or basalt (plagioclase–pyroxene); image alone cannot distinguish reliably

Rounded white pebble, likely quartz or feldspar (Most consistent with milky quartz (SiO₂), though altered feldspar or calcite is possible from the image) — mineral

Rounded white pebble, likely quartz or feldspar

Most consistent with milky quartz (SiO₂), though altered feldspar or calcite is possible from the image

Unakitized Granite (Granite / Altered Monzonite with Epidote) — igneous

Unakitized Granite

Granite / Altered Monzonite with Epidote

Diamond (Carbon (C)) — gemstone

Diamond

Carbon (C)

Petrified Wood (Silicified Wood (SiO2)) — fossil

Petrified Wood

Silicified Wood (SiO2)

Dyed Chalcedony (Agate) (Silicon Dioxide (SiO2) with artificial pigment) — mineral

Dyed Chalcedony (Agate)

Silicon Dioxide (SiO2) with artificial pigment

Diamond (Natural Diamond (Carbon, C)) — gemstone

Diamond

Natural Diamond (Carbon, C)

Quartzite Pebble (Quartzite (primarily SiO2)) — metamorphic

Quartzite Pebble

Quartzite (primarily SiO2)

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

Porphyry (likely Porphyritic Andesite or Basalt)

Porphyritic Igneous Rock

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)