Basalt
Basalt
Category
Browse igneous (anthropogenic) specimens identified by the Rock Identifier community.
Basalt
Basalt
Gold Sheen Obsidian
Volcanic Glass (Amorphous Silica with Magnetite inclusions)
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Obsidian
Volcanic glass (high silica SiO2)
Labradorite (Larvikite variety)
Plagioclase Feldspar (Na,Ca)(Al,Si)4O8 with Monzonite/Syenite matrix
Obsidian
Obsidian (Volcanic Glass)
Apache Tear
Obsidian (Hydrated Silica Rich Volcanic Glass)
Basalt Pebble
Extrusive Mafic Volcanic Rock
Scoria (Lava Rock)
Vesicular Basalt / Scoria
Basalt with Plagioclase Phenocrysts (Porphyritic Basalt)
Porphyritic Basalt (Mafic volcanic rock)
Vesicular Basalt
Extrusive mafic igneous rock; primarily (Ca,Na)(Mg,Fe,Al,Si)2O6 (Pyroxene) and (Ca,Na)Al(Al,Si)Si2O8 (Plagioclase Feldspar)
Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt with Andalusite or Feldspar laths
Granodiorite
Granodiorite
Basalt
Basalt (composition predominately Plagioclase feldspar and Pyroxene)
Granite Cobble
Felsic intrusive igneous rock (composition: SiO₂ with KAlSi₃O₈, NaAlSi₃O₈, and CaAl₂Si₂O₈)
Basalt
Basalt (Mafic volcanic rock)
Basalt (River Pebble)
Basalt (dominated by Plagioclase Feldspar and Pyroxene)
Granitic Pegmatite (River Rock specimen)
Granite / Pegmatite (composed of SiO2, KAlSi3O8, and NaAlSi3O8)
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) within Basalt (Rock)
Pumice
Pumice (a highly vesicular volcanic rock)
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) / Scoriaceous Basalt (Host Rock)
Snowflake Obsidian
Spherulitic Volcanic Glass (primarily SiO2 with Cristobalite inclusions)
Obsidian
Obsidian (principally SiO2 with MgO and Fe3O4)
Granite
Phaneritic plutonic rock (dominated by Quartz, Feldspar, and Mica)
Basalt (Greenstone)
Amygdaloidal Basalt / Chloritized Basalt
Andesite
Andesite
Granite
Phaneritic Plutonic Felsic Rock (SiO2 > 69%)
Diorite
Diorite
Obsidian (Arrowhead Lithic Tool)
Obsidian (Amorphous Volcanic Glass / SiO2 + inclusions)
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
Labradorite
Labradorite (Ca, Na)(Al, Si)4O8
Gold Ore in Quartz
Auriferous Quartz (Au + SiO2)
Lepidolite on Pegmatite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2) in Granitic Pegmatite
Tektite (likely Indochinite)
Tektite (high-silica impact glass)
Porfido (Porphyritic Rock)
Porphyry (often Rhyolitic or Andesitic)
Diorite
Diorite (Intermediate plutonic rock)
Diabase
Diabase (also known as Dolerite)
Black Obsidian
Volcanic Glass (SiO2)
Granite
Phaneritic Plutonic Felsic Rock
Pumice
Pumice (volcanic rock)
Basalt River Stone
Basalt
Black Obsidian
Obsidian (Volcanic Glass), primarily SiO2 (Silicon Dioxide)