Rock Identifier

Category

Organic Structure (Not A Rock)

Browse organic structure (not a rock) specimens identified by the Rock Identifier community.

Basalt (with possible iron oxide staining) (Mafic Igneous Rock (primarily Plagioclase and Pyroxene)) — igneous

Basalt (with possible iron oxide staining)

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Basalt (Purple-tinted scoria/vesicular variety) (Extrusive mafic igneous rock (SiO2 range 45–52%)) — igneous

Basalt (Purple-tinted scoria/vesicular variety)

Extrusive mafic igneous rock (SiO2 range 45–52%)

Basalt (tumbled/river-worn) (Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)) — igneous

Basalt (tumbled/river-worn)

Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)

Basalt (Water-worn Pebble) (Basalt (Mafic volcanic rock)) — Igneous

Basalt (Water-worn Pebble)

Basalt (Mafic volcanic rock)

Granite (Phaneritic plutonic felsic rock (primarily Quartz, Feldspar, and Mica)) — igneous

Granite

Phaneritic plutonic felsic rock (primarily Quartz, Feldspar, and Mica)

Sandstone (Arenite (SiO2 primarily)) — sedimentary

Sandstone

Arenite (SiO2 primarily)

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Pumice (Pumicite) — igneous

Pumice

Pumicite

Ferruginous Sandstone (Arenite with Iron-oxide cement) — sedimentary

Ferruginous Sandstone

Arenite with Iron-oxide cement

Vesicular Basalt (or Scoria) (Basalt (Aphanitic-Vesicular Mafic Igneous Rock)) — igneous

Vesicular Basalt (or Scoria)

Basalt (Aphanitic-Vesicular Mafic Igneous Rock)

Basalt (Mafic Igneous Rock (primarily Plagioclase and Pyroxene)) — igneous

Basalt

Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Unakite (or Epidotized Granite) (Epidotized Granite (Composition: KAlSi3O8, Ca2(Al,Fe)3(SiO4)3(OH), SiO2)) — metamorphic

Unakite (or Epidotized Granite)

Epidotized Granite (Composition: KAlSi3O8, Ca2(Al,Fe)3(SiO4)3(OH), SiO2)

Unakite (Unakite (Epidotized Granite)) — metamorphic

Unakite

Unakite (Epidotized Granite)

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)) — metamorphic

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)

Chalk (CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock) — Sedimentary

Chalk

CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock

Basalt (Basalt (Mafic igneous rock)) — igneous

Basalt

Basalt (Mafic igneous rock)

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

Basalt Beach Pebble

Basalt (Aphanitic Mafic Igneous Rock)

Basalt (Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)) — igneous

Basalt

Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)

Basalt (Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)) — igneous

Basalt

Mafic Igneous Rock (composed primarily of plagioclase, pyroxene, and olivine)

Granite (Granite (compositionally of Quartz, Alkali Feldspar, and Plagioclase)) — igneous

Granite

Granite (compositionally of Quartz, Alkali Feldspar, and Plagioclase)

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

Vesicular Basalt (Scoria)

Basalt (Vesicular)

Amygdaloidal Basalt (Amygdaloidal Basalt (Mafic silicate with secondary mineral inclusions)) — Igneous

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic silicate with secondary mineral inclusions)

Basalt (Basalt) — igneous

Basalt

Basalt

Quartz Geode (Cracked Open) (Quartz (Silicon Dioxide - SiO2)) — mineral

Quartz Geode (Cracked Open)

Quartz (Silicon Dioxide - SiO2)

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Schist (Garnet-Mica Schist) (Garnet-Mica Schist) — metamorphic

Schist (Garnet-Mica Schist)

Garnet-Mica Schist

Basalt with Plagioclase Microphenocrysts (Amygdaloidal or Porphyritic Basalt) — igneous

Basalt with Plagioclase Microphenocrysts

Amygdaloidal or Porphyritic Basalt

Dalmation Stone (often called Dalmatian Jasper) (Peralkaline Rock (Microgranite/Aplite), SiO2 with inclusions of Arfvedsonite) — igneous

Dalmation Stone (often called Dalmatian Jasper)

Peralkaline Rock (Microgranite/Aplite), SiO2 with inclusions of Arfvedsonite

Vesicular Basalt (Basalt with vesicular texture) — igneous

Vesicular Basalt

Basalt with vesicular texture

Vesicular Basalt (Basalt (principally Plagioclase and Pyroxene)) — igneous

Vesicular Basalt

Basalt (principally Plagioclase and Pyroxene)

Basalt with Calcite Veins (Aphanitic mafic volcanic rock with CaCO3 inclusions) — igneous

Basalt with Calcite Veins

Aphanitic mafic volcanic rock with CaCO3 inclusions

Unakite (Epidotized Granite (SiO2 with Ca2(Al, Fe)3(SiO4)3(OH))) — metamorphic

Unakite

Epidotized Granite (SiO2 with Ca2(Al, Fe)3(SiO4)3(OH))

Granodiorite (Gneissic Pebble) (Granodiorite displaying minor foliation) — igneous/metamorphic

Granodiorite (Gneissic Pebble)

Granodiorite displaying minor foliation

igneous/metamorphic

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Granitic Pegmatite (Granite (with coarse-grained Quartz, Feldspar, and Mica components)) — igneous

Granitic Pegmatite

Granite (with coarse-grained Quartz, Feldspar, and Mica components)

Unakite (Epidotized Granite) — metamorphic

Unakite

Epidotized Granite

Basalt (River Stone) (Basalt) — igneous

Basalt (River Stone)

Basalt

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

Sandstone (Quartzose)

Arenite (composed primarily of SiO2)

Granite (Granite (a felsic intrusive igneous rock)) — Igneous Rock

Granite

Granite (a felsic intrusive igneous rock)

Granite (Phaneritic Granitoid (Primary minerals: Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)) — igneous

Granite

Phaneritic Granitoid (Primary minerals: Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)

Porphyritic Rhyolite (Rhyolite (Porphyritic texture)) — igneous

Porphyritic Rhyolite

Rhyolite (Porphyritic texture)