Rock Identifier

Category

Igneous Rock (Volcanic Glass)

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

Peridot (Olivine) (Magnesium Iron Silicate (Mg, Fe)2SiO4) — mineral

Peridot (Olivine)

Magnesium Iron Silicate (Mg, Fe)2SiO4

Prasiolite (Green Quartz) (Silicon Dioxide (SiO2) with iron impurities) — mineral

Prasiolite (Green Quartz)

Silicon Dioxide (SiO2) with iron impurities

Peridot (Olivine ((Mg, Fe)2SiO4)) — mineral

Peridot

Olivine ((Mg, Fe)2SiO4)

Chalcedony (Chalcedony (SiO2)) — mineral

Chalcedony

Chalcedony (SiO2)

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

Carnelian Agate

Silicon Dioxide (SiO2) - variety of Chalcedony

Blue Lace Agate (Silicon Dioxide (SiO2) - Variety of Chalcedony) — mineral

Blue Lace Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Olivine (Peridot) (Magnesium Iron Silicate (Mg, Fe)2SiO4) — Mineral

Olivine (Peridot)

Magnesium Iron Silicate (Mg, Fe)2SiO4

Muscovite (Muscovite (KAl2(AlSi3O10)(OH)2)) — mineral

Muscovite

Muscovite (KAl2(AlSi3O10)(OH)2)

Brown Agate (Silicon Dioxide (SiO2)) — mineral

Brown Agate

Silicon Dioxide (SiO2)

Biotite Mica (K(Mg,Fe)3AlSi3O10(OH)2) — Mineral in a matrix (likely quartz or feldspar)

Biotite Mica

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

Mineral in a matrix (likely quartz or feldspar)

Schorl (Black Tourmaline) in Quartz or Feldspar Matrix (NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl) in Granitic Pegmatite) — igneous

Schorl (Black Tourmaline) in Quartz or Feldspar Matrix

NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl) in Granitic Pegmatite

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Granite (Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)) — igneous

Granite

Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)

Quartzite pebble (Quartzite (primarily SiO2)) — metamorphic

Quartzite pebble

Quartzite (primarily SiO2)

Moonstone (Feldspar) (Orthoclase feldspar, (K,Na)AlSi3O8) — mineral

Moonstone (Feldspar)

Orthoclase feldspar, (K,Na)AlSi3O8

Labradorite (Labradorite ((Ca, Na)(Al, Si)4O8)) — mineral

Labradorite

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

Rough Ruby (Corundum (Al2O3 with Chromium impurities)) — mineral

Rough Ruby

Corundum (Al2O3 with Chromium impurities)

Smoky Quartz (Silicon Dioxide (SiO2)) — mineral

Smoky Quartz

Silicon Dioxide (SiO2)

Serpentine (Serpentine Group (primarily Antigorite or Lizardite), Mg3Si2O5(OH)4) — metamorphic

Serpentine

Serpentine Group (primarily Antigorite or Lizardite), Mg3Si2O5(OH)4

Sandstone (Clastic sedimentary rock (primarily SiO2)) — sedimentary

Sandstone

Clastic sedimentary rock (primarily SiO2)

Granite Cobble / Rounded Granite River Rock (Granite) — Igneous

Granite Cobble / Rounded Granite River Rock

Granite

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Sandstone (with Lichen) (Arenite (composed primarily of SiO2)) — sedimentary

Sandstone (with Lichen)

Arenite (composed primarily of SiO2)

Sandstone (with Iron Staining) (Clastic sedimentary rock (SiO2 with Fe2O3 impurities)) — sedimentary

Sandstone (with Iron Staining)

Clastic sedimentary rock (SiO2 with Fe2O3 impurities)

Sandstone (with Iron Staining) (Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)) — sedimentary

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)

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

Sandstone

Arenite (composed primarily of SiO2)

Sandstone (Weathered) (Arenite (primarily SiO2)) — sedimentary

Sandstone (Weathered)

Arenite (primarily SiO2)

Sandstone (Quartz-rich) (Arenite (composed mainly of SiO2)) — sedimentary

Sandstone (Quartz-rich)

Arenite (composed mainly of SiO2)

Sandstone (Quartzose) (Arenite (primarily SiO2)) — sedimentary

Sandstone (Quartzose)

Arenite (primarily SiO2)

Sandstone (clastic) (Clastic Sedimentary Rock (primarily composed of SiO2)) — sedimentary

Sandstone (clastic)

Clastic Sedimentary Rock (primarily composed of SiO2)

Quartz (Milky to Clear) (Silicon Dioxide (SiO2)) — mineral

Quartz (Milky to Clear)

Silicon Dioxide (SiO2)

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

Gneiss

Gneiss (High-grade metamorphic rock)

Quartz Crystal (Quartz (SiO₂)) — Mineral

Quartz Crystal

Quartz (SiO₂)

Blue Chalcedony (Silicon Dioxide (SiO2) - Cryptocrystalline Quartz) — mineral

Blue Chalcedony

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Amethyst (Purple), Sulfur (Yellow), and Blue Apatite (SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)) — mineral

Amethyst (Purple), Sulfur (Yellow), and Blue Apatite

SiO2 (Quartz), S (Native Sulfur), Ca5(PO4)3(F,Cl,OH) (Apatite Group)

Green Fluorite (Calcium Fluoride (CaF2)) — mineral

Green Fluorite

Calcium Fluoride (CaF2)

Amethyst (Amethyst (Silicon Dioxide containing trace Iron impurities, SiO2)) — mineral

Amethyst

Amethyst (Silicon Dioxide containing trace Iron impurities, SiO2)

Blue Chalcedony (Blue Lace Agate variety) (Silicon Dioxide (SiO₂)) — mineral

Blue Chalcedony (Blue Lace Agate variety)

Silicon Dioxide (SiO₂)

Blue Lace Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Blue Lace Agate

Cryptocrystalline Quartz (SiO2)

Banded Agate (Cryptocrystalline Quartz (SiO2)) — mineral

Banded Agate

Cryptocrystalline Quartz (SiO2)

Picture Jasper (Silicon Dioxide (SiO2) with iron oxide and clay inclusions) — sedimentary

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and clay inclusions

Gneiss (Foliated Metamorphic Rock (Gneiss)) — metamorphic

Gneiss

Foliated Metamorphic Rock (Gneiss)