Porphyry
Porphyritic Basalt or Porphyritic Andesite
Category
Browse igneous rock specimens identified by the Rock Identifier community.
Porphyry
Porphyritic Basalt or Porphyritic Andesite
Granite
Phaneritic Plutonic Rock (primarily Quartz, Feldspar, and Mica/Amphibole)
Granite (Pink/Red Orthoclase variety)
Phaneritic Plutonic Felsic Rock (SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8)
Basalt (River Cobble)
Mafic Igneous Basalt (composed primarily of Plagioclase feldspar, Pyroxene, and Olivine)
Basalt with Secondary Mineralization (Likely Zeolites or Calcite)
Aphanitic mafic volcanic rock with secondary mineral inclusions (e.g., CaAl2Si3O10·3H2O for Scolecite)
Basalt
Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)
Pink Granite
Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)
Quartz (Milky or Clear variety)
Silicon Dioxide (SiO2)
Vesicular Basalt with Quartz
Vesicular Basalt (SiO2 inclusions)
Milky Quartz (Water-worn Pebble)
Silicon Dioxide (SiO2)
Porphyritic Basalt (Chinese Writing Stone or Flower Stone)
Porphyritic Basalt / Porphyry
Limonite-stained Quartz
Silicon Dioxide (SiO2) with Iron Oxide/Hydroxide (FeO(OH)·nH2O) staining
Dolerite (Diabase)
Dolerite / Diabase
Granite
Phaneritic Granitoid (Primary minerals: Quartz SiO2, Feldspar KAlSi3O8, and Biotite/Mica)
Pumice
Pumice (a highly vesicular volcanic rock)
Milky Quartz (among River Rock)
Quartz (Silicon Dioxide, SiO2)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxide
Quartz (Milky/Smoky variety on matrix)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Clear Quartz Crystal
Silicon Dioxide (SiO2)
Chalcedony (Agate/Carnelian precursor)
Chalcedony (Silicon Dioxide, SiO2)
Pumice
Vesicular volcanic glass (primarily SiO2)
Scoria (Lava Rock)
Mafic Volcanic Scoria
Basalt with Quartz/Calcite Veins
Basalt (Aphanitic Mafic Volcanic Rock) with Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) inclusions
Granite
Phaneritic Plutonic Felsic Rock (Granite)
Porphyritic Basalt
Porphyritic Basalt (containing Plagioclase or Alkali Feldspar phenocrysts)
Pumice
Pumice (volcanic glass foam)
Amygdaloidal Basalt
Basalt with secondary amygdule minerals (likely Epidote or Chlorite)
Granodiorite
Granodiorite
Andesite
Andesite
Pumice
Pumicite (Amorphous Volcanic Glass)
Basalt
Basalt
Crushed Granite Gravel
Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase Feldspar)
Pumice
Pumice (Vesicular volcanic glass)
Pumice
Pumice (volcanic glass froth)
Basalt
Basalt (composition of plagioclase, pyroxene, and olivine)
Pumice
Pumice (a highly vesicular volcanic glass)
Mahogany Obsidian
Volcanic Glass (predominantly SiO2 with Fe2O3 inclusions)
Basalt
Basalt (SiO2 percentage between 45% and 52%)
Pumice
Pumicite / Vesicular Rhyolite
Eclogite
Eclogite (Omphacite-Garnet rock)
Granite
Phaneritic plutonic rock (SiO2 range 65-75%)