Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Category
Browse igneous (anthropogenic) specimens identified by the Rock Identifier community.
Granite
Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)
Pumice
Pumice (a highly vesicular volcanic glass)
Andesite
Andesite (Intermediate Extrusive Volcanic Rock)
Basalt River Stone
Basalt (Mafic volcanic rock)
Vesicular Basalt (River Rock)
Afanitic Vesicular Basalt
Pumice
Pumice (a highly vesicular volcanic rock)
Basalt (River Rock/Cobble)
Basalt (no specific mineral formula as it's a rock)
Granite
Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)
Basalt
Basalt (composition of plagioclase feldspar and pyroxene)
Porphyritic Basalt
Amygdaloidal Porphyritic Basalt
Olivine (Peridotite)
(Mg,Fe)2SiO4 (Magnesium Iron Silicate)
Porphyry
Porphyritic Rhyolite or Andesite
Mahogany Obsidian
Volcanic Glass with Hematite/Magnetite (SiO2 + Fe2O3)
Basalt with Plagioclase Microphenocrysts
Amygdaloidal or Porphyritic Basalt
Obsidian
Volcanic Glass (SiO2, usually 70% or more)
Pumice
Pumice (Vesicular volcanic glass)
Scoria (Lava Rock)
Scoria (Vesicular Basaltic Glass/Rock)
Vesicular Basalt
Extrusive Basalt (Mafic Silicate)
Porphyritic Basalt (with Amygdales)
Amygdaloidal Porphyritic Basalt
Obsidian
Volcanic Glass (70-75% SiO2 with MgO and Fe3O4)
Granite Pebble
Granite
Obsidian (likely Golden Sheen Obsidian or Rainbow Obsidian, given the subtle sheen visible on some beads)
Obsidian (volcanic glass, predominantly SiO2 with various impurities)
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 with impurities)
Granite
Granite (primarily Quartz, Feldspar, and Mica)
Basalt (Vesicular)
Basalt (Extrusive Volcanic Rock)
Basalt with Iron Oxidation (Lattice/Veined)
Mafic Volcanic Rock (principally Plagioclase and Pyroxene)
Porphyry
Porphyritic Andesite/Basalt
Diorite (Salt and Pepper Rock)
Phaneritic Plutonic Diorite; chemical composition roughly 52-63% silica (SiO2)
Basalt
Aphanitic mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Vesicular Basalt (Amygdaloidal)
Vesicular Basalt (Fe-Mg rich extrusive volcanic rock)
Basalt with Plagioclase Phenocrysts
Porphyritic Basalt
Obsidian
Volcanic glass (high silica volcanic rock)
Diorite (Porphyritic)
Porphyritic Diorite
Porphyritic Basalt (Chinese Writing Stone)
Porphyritic Basalt or Porphyritic Andesite
Granite River Pebble
Phaneritic Granite (primarily Quartz, Feldspar, and Mica)
Granite (Alkali-feldspar Granite)
Felsic Plutonic Rock (Primary minerals: Quartz SiO2, Orthoclase KAlSi3O8, Plagioclase (Na,Ca)AlSi3O8)
Granite
Granite (a phaneritic intrusive igneous rock consisting mainly of quartz, alkali feldspar, and plagioclase)
Indigo Gabbro
Gabbro (Mafic Intrusive Rock)
Granite Pebble
Granite
Granite
Granite (Felsic Plutonic Rock)
Basalt (Vesicular/Amygdaloidal or Water-Worn)
Basalt
Crushed Granite Gravel
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase Feldspar)