Rock Identifier

Category

Igneous Rock (Volcanic Glass)

Browse igneous rock (volcanic glass) specimens identified by the Rock Identifier community.

Amethyst on Agate/Basalt Matrix (Silicon Dioxide (SiO2) with iron impurities) — mineral

Amethyst on Agate/Basalt Matrix

Silicon Dioxide (SiO2) with iron impurities

mineral
Dalmatian Jasper (Dalmatian Stone) (Peralkaline rhyolite) — igneous

Dalmatian Jasper (Dalmatian Stone)

Peralkaline rhyolite

igneous
Biotite Gneiss (Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)) — metamorphic

Biotite Gneiss

Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)

metamorphic
Banded Agate (Silicon Dioxide (SiO2) - Chalcedony variety) — mineral

Banded Agate

Silicon Dioxide (SiO2) - Chalcedony variety

mineral
Quartzite (Quartzite (primarily SiO2)) — metamorphic

Quartzite

Quartzite (primarily SiO2)

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

Milky Quartz

Silicon Dioxide (SiO2)

mineral
Jasper / Chert (River Pebble) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Jasper / Chert (River Pebble)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

sedimentary
Quartzite Pebble (Quartzite (primarily SiO2)) — metamorphic

Quartzite Pebble

Quartzite (primarily SiO2)

metamorphic
Granitic Gneiss (Gneiss (High-grade Metamorphic Rock)) — metamorphic

Granitic Gneiss

Gneiss (High-grade Metamorphic Rock)

metamorphic
Granite Cobble (Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)) — igneous

Granite Cobble

Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)

igneous
Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

metamorphic
Rhyolite (Rhyolite) — igneous

Rhyolite

Rhyolite

igneous
Muscovite Mica (in Quartz/Feldspar Matrix) (Muscovite - KAl2(AlSi3O10)(OH)2) — mineral

Muscovite Mica (in Quartz/Feldspar Matrix)

Muscovite - KAl2(AlSi3O10)(OH)2

mineral
Green Aventurine (Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2) — mineral

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2 + K(Al,Cr)2AlSi3O10(OH)2

mineral
Gneiss (Gneiss) — metamorphic

Gneiss

Gneiss

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

Granite Gneiss

Gneiss (high-grade metamorphic rock)

metamorphic
Quartzite (Water-worn Cobble) (Quartzite (Composition: 90%+ SiO2)) — metamorphic

Quartzite (Water-worn Cobble)

Quartzite (Composition: 90%+ SiO2)

metamorphic
Sandstone (Quartzose Sandstone) (Clastic Sedimentary Rock - Arenite) — sedimentary

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock - Arenite

sedimentary
Iron-stained Quartz (Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3/FeO(OH))) — mineral

Iron-stained Quartz

Silicon Dioxide with Iron Oxide (SiO2 + Fe2O3/FeO(OH))

mineral
Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

sedimentary
Quartz (Crystal/Druzy Quartz) (Quartz (SiO₂)) — Mineral

Quartz (Crystal/Druzy Quartz)

Quartz (SiO₂)

Mineral
Geode (Unopened) (Siliceous Septarian Concretion / Geode (SiO2)) — sedimentary

Geode (Unopened)

Siliceous Septarian Concretion / Geode (SiO2)

sedimentary
Almandine Garnet (Iron aluminum silicate (Fe3Al2(SiO4)3)) — mineral

Almandine Garnet

Iron aluminum silicate (Fe3Al2(SiO4)3)

mineral
Sandstone (Arenite (SiO2 primarily)) — sedimentary

Sandstone

Arenite (SiO2 primarily)

sedimentary
Red Moss Agate (Jasper) (Silicon Dioxide (SiO2) with Iron Oxide inclusions) — sedimentary

Red Moss Agate (Jasper)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

sedimentary
Yellow Chalcedony (Agate/Chert) (Silicon Dioxide (SiO2) - Cryptocrystalline Quartz) — sedimentary

Yellow Chalcedony (Agate/Chert)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

sedimentary
Biotite Mica (Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)) — mineral

Biotite Mica

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

mineral
Gneiss (Metamorphic Rock) (Gneiss) — metamorphic

Gneiss (Metamorphic Rock)

Gneiss

metamorphic
Quartz (Iron-Stained) (Silicon Dioxide (SiO2)) — mineral

Quartz (Iron-Stained)

Silicon Dioxide (SiO2)

mineral
Granite (specifically Pink or Alkali Feldspar Granite) (Felsic Plutonic Rock (primarily SiO2 with KAlSi3O8)) — igneous

Granite (specifically Pink or Alkali Feldspar Granite)

Felsic Plutonic Rock (primarily SiO2 with KAlSi3O8)

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

Milky Quartz

Silicon Dioxide (SiO2)

mineral
Gneiss (Gneiss (High-grade Metamorphic Rock)) — metamorphic

Gneiss

Gneiss (High-grade Metamorphic Rock)

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

Gneiss

Gneiss (High-grade metamorphic rock)

metamorphic
Basalt (Basalt (Mafic Extrusive)) — igneous

Basalt

Basalt (Mafic Extrusive)

igneous
Black Tourmaline (Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)) — Mineral

Black Tourmaline

Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Mineral
Banded Gneiss (Gneiss (complex metamorphic silicate rock)) — metamorphic

Banded Gneiss

Gneiss (complex metamorphic silicate rock)

metamorphic
Black Onyx (Silicon Dioxide (SiO2)) — mineral

Black Onyx

Silicon Dioxide (SiO2)

mineral
Carnelian (a variety of Chalcedony) (Cryptocrystalline Quartz (SiO2) with iron oxide inclusions) — Mineral

Carnelian (a variety of Chalcedony)

Cryptocrystalline Quartz (SiO2) with iron oxide inclusions

Mineral
Granitic Gneiss (Gneiss (Metamorphic rock of granitic composition)) — metamorphic

Granitic Gneiss

Gneiss (Metamorphic rock of granitic composition)

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

Gneiss

Gneiss (High-grade regional metamorphic rock)

metamorphic
Gneiss (Gneiss) — metamorphic

Gneiss

Gneiss

metamorphic
Dyed Pink Agate Slice (Cryptocrystalline variety of Quartz (SiO2)) — mineral

Dyed Pink Agate Slice

Cryptocrystalline variety of Quartz (SiO2)

mineral