Basalt
Extrusive mafic igneous rock
Category
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Basalt
Extrusive mafic igneous rock
Chert (White Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Marble
Recrystallized Calcite (CaCO3) Rock
Mica Schist
Crystalline Schist (often primarily Muscovite or Biotite sheet silicates)
Smoky Quartz
SiO2 (Silicon Dioxide with aluminum impurities)
Quartzite
Metamorphic Quartzite (predominantly SiO2)
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
Milky Quartz with Iron Staining
Quartz (Silicon Dioxide - SiO2)
Red Granite
Granite (Felsic Plutonic Rock)
Milky Quartz with Mineral Inclusions
Quartz (Silicon Dioxide, SiO2)
Labradorite
(Ca, Na)(Al, Si)4O8
Quartzite
Quartzite (composed primarily of SiO2)
Druzy Quartz
Silicon Dioxide (SiO2)
Granite
Granite
Porphyritic Basalt
Basalt (with plagioclase phenocrysts)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milky Quartz (with Iron Oxide staining)
Quartz (Silicon Dioxide - SiO2)
Chert (specifically Chert Nodule/Flint)
Chert (Silicon Dioxide, SiO2)
Pink Dyed Agate (Banded Chalcedony)
Silicon dioxide (SiO2) - variety Chalcedony
Schist
Mica Schist (Medium-grade Metamorphic Rock)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Kyanite (in Schist Matrix)
Kyanite (Al2SiO5)
Pink Granite (Gneissic Granite)
Granite (composed primarily of Quartz, K-Feldspar, and Plagioclase)
Yellow Calcite
Calcium Carbonate (CaCO3)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Smoky Quartz
Silicon Dioxide (SiO2)
Red Granite
Phaneritic Felsic Igneous Rock
Schist
Crystalline Schist (often containing Muscovite, Biotte, or Quartz)
Milky Quartz
Silicon Dioxide (SiO2)
Yellow Quartzite (River Pebble)
Quartzite (primarily Silicon Dioxide, SiO2)
Limestone (specifically Bituminous or Carbonaceous Limestone)
Calcium Carbonate (CaCO3) with Organic Impurities
Sodalite
Sodalite (Na8(Al6Si6O24)Cl2)
Chert (Gravel pebble)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Anthracite Coal
Anthracite (Carbon based)
Vesicular Basalt
Basalt
Quartz Pebble
Silicon Dioxide (SiO2)
Diabase (also known as Dolerite)
Diabase / Microgabbro
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
Painted River Pebble (likely Basalt or Greywacke)
Aphanitic Lithic Clast with Anthropogenic Pigment coating
Red Sandstone (Old Red Sandstone Pebble)
Arenite with iron oxide (Fe2O3) cement
Amethyst
Amethyst (Silicon Dioxide, SiO2)