Rock Identifier

Category

Mineral, Specifically A Detrital Grain

Browse mineral, specifically a detrital grain specimens identified by the Rock Identifier community.

Mahogany Obsidian (Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)) — igneous

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)

Chert (Black Chert/Flint) (Chert (Silicon Dioxide, SiO2)) — sedimentary

Chert (Black Chert/Flint)

Chert (Silicon Dioxide, SiO2)

Prehnite (Prehnite - Ca2Al(AlSi3O10)(OH)2) — mineral

Prehnite

Prehnite - Ca2Al(AlSi3O10)(OH)2

Pink Granite / Gneiss (Felsic Plutonic Rock (Granite) with Gneissic banding) — igneous / metamorphic

Pink Granite / Gneiss

Felsic Plutonic Rock (Granite) with Gneissic banding

igneous / metamorphic

Chert (specifically Gray Chert) (Chert (SiO2)) — sedimentary

Chert (specifically Gray Chert)

Chert (SiO2)

Granite Gneiss (Gneiss (High-grade metamorphic rock)) — metamorphic

Granite Gneiss

Gneiss (High-grade metamorphic rock)

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

Quartz (Milky/Opaque variety)

Silicon Dioxide (SiO2)

Chert or Flint (polished/water-worn) (Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.) — Sedimentary (most likely, as Chert is a sedimentary rock often found as nodules in limestone or as bedded deposits; however, it can also form by metasomatic replacement, which leans towards metamorphic processes under certain conditions)

Chert or Flint (polished/water-worn)

Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.

Sedimentary (most likely, as Chert is a sedimentary rock often found as nodules in limestone or as bedded deposits; however, it can also form by metasomatic replacement, which leans towards metamorphic processes under certain conditions)

Obsidian (specifically Mahogany Obsidian) (Volcanic glass (high silica content, SiO2)) — igneous

Obsidian (specifically Mahogany Obsidian)

Volcanic glass (high silica content, SiO2)

Ferruginous Quartzite (Chert) (Quartzite with Iron inclusions (SiO2 + Fe2O3)) — metamorphic

Ferruginous Quartzite (Chert)

Quartzite with Iron inclusions (SiO2 + Fe2O3)

Moonstone (specifically Rainbow Moonstone / White Labradorite) (White Labradorite (Feldspar Group: (Na,Ca)(Al,Si)4O8)) — mineral

Moonstone (specifically Rainbow Moonstone / White Labradorite)

White Labradorite (Feldspar Group: (Na,Ca)(Al,Si)4O8)

White Quartz (Milky Quartz) (Silicon Dioxide (SiO2)) — mineral

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Quartz (specifically Quartzite or Massive Quartz) (Silicon Dioxide (SiO2)) — Mineral

Quartz (specifically Quartzite or Massive Quartz)

Silicon Dioxide (SiO2)

Banded Gneiss (River Rock/Pebble) (Gneiss (specifically a banded variety, likely a orthogneiss or paragneiss depending on parent rock)) — Metamorphic Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety, likely a orthogneiss or paragneiss depending on parent rock)

Metamorphic Rock

Petrified Wood (Silicified wood (primarily SiO2)) — metamorphic

Petrified Wood

Silicified wood (primarily SiO2)

Fossil Shell in Sedimentary Matrix (Bivalvia (fossil) in Calcium Carbonate Matrix) — sedimentary

Fossil Shell in Sedimentary Matrix

Bivalvia (fossil) in Calcium Carbonate Matrix

Carnelian Agate/Jasper blend (Silicon Dioxide (SiO2) - variety of Chalcedony) — mineral

Carnelian Agate/Jasper blend

Silicon Dioxide (SiO2) - variety of Chalcedony

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

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Green Druzy Quartz (Prasiolite) (Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)) — mineral

Green Druzy Quartz (Prasiolite)

Silicon Dioxide (SiO2) with inclusions (typically Chlorite or Actinolite)

Quartzite (Metamorphosed Sandstone (Mainly SiO2)) — metamorphic

Quartzite

Metamorphosed Sandstone (Mainly SiO2)

Orange Calcite (Calcium Carbonate (CaCO3)) — mineral

Orange Calcite

Calcium Carbonate (CaCO3)

Green Aventurine (Aventurine Quartz (SiO2 with Fuchsite inclusions)) — metamorphic

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Ocean Jasper (Silicon Dioxide (SiO2) with various inclusions) — Mineral (Variety of Quartz)

Ocean Jasper

Silicon Dioxide (SiO2) with various inclusions

Mineral (Variety of Quartz)

Yellow Jasper (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

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

Petrified Wood

Silicified wood (primarily SiO2)

Petrified Wood (Silicified Wood (SiO2)) — metamorphic

Petrified Wood

Silicified Wood (SiO2)

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

Chert / Jasper

Microcrystalline Quartz (SiO2)

Chert Nodule (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Nodule

Microcrystalline Quartz (SiO2)

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

Petrified Wood

Silicified Wood (primarily SiO2)

Basalt (Basalt (High-iron/magnesium silicate rock)) — igneous

Basalt

Basalt (High-iron/magnesium silicate rock)

Basalt Pebble with Quartz Veining (Basalt (extrusive volcanic rock)) — igneous

Basalt Pebble with Quartz Veining

Basalt (extrusive volcanic rock)

Quartzite Cobble (Quartzite (primarily SiO2)) — metamorphic

Quartzite Cobble

Quartzite (primarily SiO2)

Porphyritic Basalt (Basalt (with plagioclase phenocrysts)) — igneous

Porphyritic Basalt

Basalt (with plagioclase phenocrysts)

Specular Hematite (Specularite) (Iron Oxide (Fe2O3)) — mineral

Specular Hematite (Specularite)

Iron Oxide (Fe2O3)

Green Calcite (Calcium Carbonate (CaCO3)) — mineral

Green Calcite

Calcium Carbonate (CaCO3)

Quartz (Quartz (SiO2 - Silicon Dioxide)) — Mineral

Quartz

Quartz (SiO2 - Silicon Dioxide)

Shale or Siltstone (Sedimentary Rock (Siliciclastic)) — sedimentary

Shale or Siltstone

Sedimentary Rock (Siliciclastic)

Plagioclase Feldspar (specifically Albite/Oligoclase) ((Na,Ca)(Si,Al)4O8) — mineral

Plagioclase Feldspar (specifically Albite/Oligoclase)

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

Moonstone (specifically White Moonstone/Adularia) (Potassium aluminum silicate ((K,Na)AlSi3O8)) — mineral

Moonstone (specifically White Moonstone/Adularia)

Potassium aluminum silicate ((K,Na)AlSi3O8)

Garnet (specifically Almandine or Pyrope) (Almandine (Fe3Al2Si3O12) or Pyrope (Mg3Al2Si3O12)) — mineral

Garnet (specifically Almandine or Pyrope)

Almandine (Fe3Al2Si3O12) or Pyrope (Mg3Al2Si3O12)

Chalcedony (specifically Agate or Water-worn Quartzite) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (specifically Agate or Water-worn Quartzite)

Silicon Dioxide (SiO2)