Rock Identifier

Category

Igneous Rock (Volcanic Glass)

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

Chert (often called Flint in dark varieties) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint in dark varieties)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Jasper (Jasper (Silicon Dioxide, SiO2 with Fe2O3 inclusions)) — mineral

Red Jasper

Jasper (Silicon Dioxide, SiO2 with Fe2O3 inclusions)

Sandstone (Arenite (SiO2 predominantly)) — sedimentary

Sandstone

Arenite (SiO2 predominantly)

Olivine in Basalt (Peridotite / Forsterite ((Mg,Fe)2SiO4)) — igneous

Olivine in Basalt

Peridotite / Forsterite ((Mg,Fe)2SiO4)

Diabase (Diabase (also known as Dolerite)) — igneous

Diabase

Diabase (also known as Dolerite)

Dalmatian Stone (Peralkaline Quartz-Feldspar Rock with Arfvedsonite) — igneous

Dalmatian Stone

Peralkaline Quartz-Feldspar Rock with Arfvedsonite

Garnet (Almandine formula: Fe3Al2(SiO4)3) — mineral

Garnet

Almandine formula: Fe3Al2(SiO4)3

Sandstone (Calcareous Sandstone) (Calcareous Sandstone (primarily SiO2 with CaCO3 cement)) — sedimentary

Sandstone (Calcareous Sandstone)

Calcareous Sandstone (primarily SiO2 with CaCO3 cement)

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

Peridot

Olivine ((Mg,Fe)2SiO4)

Decomposed Granite (Grano-diorite/Granite-residuum (SiO2 primary)) — igneous

Decomposed Granite

Grano-diorite/Granite-residuum (SiO2 primary)

Quartz (likely) or a Quartzite Pebble (Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.) — Mineral, specifically a detrital grain

Quartz (likely) or a Quartzite Pebble

Silicon dioxide (SiO2) for quartz. If it's quartzite, it's a metamorphic rock primarily composed of quartz.

Mineral, specifically a detrital grain

Carnelian (Carnelian Agate) (Carnelian (Silicon Dioxide - SiO2)) — mineral

Carnelian (Carnelian Agate)

Carnelian (Silicon Dioxide - SiO2)

Carnelian Agate (Silicon Dioxide (SiO2) - Chalcedony containing Iron Oxide impurities) — mineral

Carnelian Agate

Silicon Dioxide (SiO2) - Chalcedony containing Iron Oxide impurities

Ferruginous Quartzite (Iron-stained Quartzite) (Quartzite with Iron oxides (FeO(OH) / Fe2O3)) — metamorphic

Ferruginous Quartzite (Iron-stained Quartzite)

Quartzite with Iron oxides (FeO(OH) / Fe2O3)

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

Green Aventurine

Aventurine Quartz (SiO2 with Fuchsite inclusions)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

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

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Basalt (Basalt (dominated by Plagioclase Feldspar and Pyroxene)) — igneous

Basalt

Basalt (dominated by Plagioclase Feldspar and Pyroxene)

Milk Quartz (with Iron staining) (Silicon Dioxide (SiO2)) — mineral

Milk Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Diorite (Diorite) — igneous

Diorite

Diorite

Sandstone (Arenite) — sedimentary

Sandstone

Arenite

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

Sandstone

Arenite (composed primarily of SiO2)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

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

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 oxides)

Sandstone (Arenite (primarily SiO2)) — sedimentary

Sandstone

Arenite (primarily SiO2)

Green Glass Slag (Amorphous Silicon Dioxide (SiO2) with metal oxide impurities) — mineraloid (man-made)

Green Glass Slag

Amorphous Silicon Dioxide (SiO2) with metal oxide impurities

mineraloid (man-made)

Sandstone (Quartzose Sandstone) (Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)) — sedimentary

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)

Quartzite Pebble (Recrystallized Quartz (SiO2)) — metamorphic

Quartzite Pebble

Recrystallized Quartz (SiO2)

Granitic Sand (Detrital sediment (predominantly Quartz, Feldspar, and Mica)) — sedimentary

Granitic Sand

Detrital sediment (predominantly Quartz, Feldspar, and Mica)

Quartzite (Quartzite (SiO2)) — metamorphic

Quartzite

Quartzite (SiO2)

Petrified Wood (Silicified Wood (primarily SiO₂ / Silicon Dioxide)) — mineral

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Amethyst (Quartz) (Amethyst (SiO2 with iron impurities)) — mineral

Amethyst (Quartz)

Amethyst (SiO2 with iron impurities)

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

Carnelian

SiO2 (Silicon Dioxide) - Carnelian variety of Chalcedony

Turquoise in Matrix (Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O) — mineral

Turquoise in Matrix

Hydrous phosphate of copper and aluminium, CuAl6(PO4)4(OH)8·4H2O

Biotite Mica in Host Rock (Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)) — mineral

Biotite Mica in Host Rock

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

Blue Sapphire (Corundum (Al2O3 - Aluminum Oxide)) — mineral

Blue Sapphire

Corundum (Al2O3 - Aluminum Oxide)

Chert (Nodule) (Microcrystalline or Cryptocrystalline Silica (SiO2)) — sedimentary

Chert (Nodule)

Microcrystalline or Cryptocrystalline Silica (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2 - Silicon Dioxide)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2 - Silicon Dioxide)

Geode (unopened) (Calcedony-lined Geode (SiO2)) — sedimentary

Geode (unopened)

Calcedony-lined Geode (SiO2)

Corundum (Sapphire in Host Rock) (Corundum (Aluminum Oxide, Al2O3)) — mineral

Corundum (Sapphire in Host Rock)

Corundum (Aluminum Oxide, Al2O3)

Sandstone (Arenite (SiO2 principal)) — sedimentary

Sandstone

Arenite (SiO2 principal)

Quartz (Translucent/Rose variety) (Silicon Dioxide (SiO2)) — mineral

Quartz (Translucent/Rose variety)

Silicon Dioxide (SiO2)