Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Category
Browse igneous and sedimentary mixture specimens identified by the Rock Identifier community.
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurities)
Obsidian
Volcanic Glass (predominantly SiO2)
Diorite
Phaneritic Intrusive Igneous Rock (composed of Plagioclase feldspar, Hornblende, and Biotite)
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic silicate with secondary mineral inclusions)
Obsidian
Obsidian (Volcanic Glass)
Pumice
Pumice (volcanic glass formed of highly vesicular rough textured rock)
Obsidian
Volcanic Glass (SiO2 - Silicon Dioxide with impurities)
Obsidian
Volcanic glass (SiO2-rich extrusive igneous rock)
Diabase (Greenstone)
Diabase (Dolerite)
Porphyritic Rhyolite (Cookie Stone)
Porphyritic Rhyolite (SiO2, with phenocrysts)
Yooperlite (Sodalite-bearing Syenite)
Sodalite-rich Syenite (Na8(Al6Si6O24)Cl2)
Granite
Granite (composed primarily of Quartz SiO2, Alkali Feldspar (K,Na)AlSi3O8, and Plagioclase Feldspar)
Pink Granite (Potassium-rich Granite)
Phaneritic Felsic Igneous Rock (primarily SiO2, Al2O3, K2O)
Basalt with Quartz Veins
Basalt (complex silicate) with Quartz (SiO2) intrusions
Basalt (Amygdaloidal)
Amygdaloidal Basalt
Granite (Pink/Red variety)
Phaneritic Felsic Intrusive Igneous Rock (composed primarily of Quartz, K-Feldspar, and Plagioclase)
Obsidian
Obsidian (principally SiO2/Silicon dioxide)
Diorite
Phaneritic intermediate plutonic rock
Granite
Phaneritic Igneous Rock (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)
Granite
Granite
Pink Granite
Phaneritic Plutonic Felsic Rock (K-feldspar rich)
Porphyritic Basalt
Porphyritic Basalt (with Plagioclase phenocrysts)
Slag (Industrial Glass)
Anthropogenic Vitreous Slag (Post-industrial byproduct)
Graphic Granite (Zebra Rock)
Pegmatitic Granite (composed of Quartz and K-Feldspar)
Porphyry
Porphyritic Igneous Rock (likely Porphyritic Andesite or Basalt)
Pink Granite (Crystalline Granite)
Igneous Intrusive Rock (Felsic Plutonic)
Tektite (Indochinite)
Tektite (Amorphous Silica Glass), SiO2(Al2O3)
Granodiorite with Quartz Veining
Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins
Coarse-grained Quartz with Feldspar inclusions
Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions
Red Scoria (Lava Rock)
Scoria (Extrusive Igneous Rock / Mafic composition)
Garnet Rhyolite
Rhyolite (high-silica volcanic rock) with almandine/spessartine garnet
Obsidian
Volcanic Glass (Primary component: SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
Red Rhyolite Porphyry
Rhyolite (Porphyritic texture)
Granite with Orthoclase and Hematite Staining
Phaneritic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)
Feldspathic Granite (likely Syenite or Granite Pegmatite)
Phaneritic Acidic Igneous Rock (KAlSi3O8 dominant with SiO2)
Granodiorite
Granodiorite (phaneritic intrusive igneous rock)
Mahogany Obsidian
Obsidian (Volcanic Glass) with Hematite or Magnetite inclusions, SiO2 (Silicon Dioxide)
Porphyritic Rhyolite (Red Rhyolite)
Rhyolite (Porphyry)
Coarse-grained Granite (Quartz and Feldspar dominated)
Granitoid (KAlSi3O8 – NaAlSi3O3 – CaAl2Si2O8 – SiO2)
Granite
Phaneritic high-silica plutonic rock (composed primarily of Quartz, Feldspar, and Mica)
Smoky Quartz in Matrix
Silicon dioxide (SiO2) within Pegmatite/Gneiss