Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Igneous Rock
Category
Organic Mineral
Browse organic mineral specimens identified by the Rock Identifier community.
Black Sapphire
Corundum (Al2O3 with iron and titanium impurities)
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Kimberlite with Diamond
Kimberlite (Diamond formula: C)
igneous
Diorite (Polished River Pebble)
Diorite (Intermediate intrusive igneous rock)
igneous
Gneiss
Gneiss (Metamorphic rock composed primarily of quartz, feldspar, and mica)
metamorphic
Mica Schist with Quartz
Mica-Quartz Schist (Muscovite subclass)
metamorphic
Diorite
Diorite (plutonic igneous rock)
igneous
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Pink Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Shale
Fissile Mudrock (Clay-rich Sedimentary Rock)
sedimentary
Rhodochrosite
Manganese Carbonate (MnCO3)
mineral
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Granite
Granite (composed primarily of Quartz SiO2, Potassium Feldspar KAlSi3O8, and Plagioclase)
Igneous
Azurite-Malachite (often a mixed specimen)
Azurite: Cu3(CO3)2(OH)2; Malachite: Cu2(CO3)(OH)2. The specimen appears to be a natural mixture or intergrowth of these two minerals.
Mineral
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Sedimentary
Strawberry Quartz
Quartz (SiO2) with inclusions of Goethite or Hematite
Mineral
Limonite (Iron Stone/Ocher)
Limonite (FeO(OH)·nH2O)
mineral
Vesicular Basalt with Secondary Mineral Inclusions
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Greenstone
Greenschist (containing chlorite, epidote, and actinolite)
metamorphic
Geode with Iron-Stained Quartz/Calcite
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3) in Sedimentary Matrix
sedimentary
Psilomelane (Black Hematite/Manganese Ore)
Barium Manganese Oxide (Formula: BaMn9O18(OH)4)
mineral
Red Sandstone
Arenite (primarily Quartz SiO2 with Hematite Fe2O3 cement)
sedimentary
Red Sandstone
Arenite (primarily composed of SiO2 with Fe2O3 cement)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Chrysocolla on Matrix
Hydrated copper phyllosilicate (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Tiger's Eye
Tiger's Eye (SiO2 with crocidolite inclusions)
mineral
Tumbled Stones (various)
Mixed Silica-based Minerals (primarily Quartz and Chalcedony)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with inclusions of Dumortierite or similar minerals
mineral
Dumortierite Quartz
Al7BO3(SiO4)3O3 (Borosilicate mineral/Quartz inclusion)
mineral
Chrysocolla
Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)
mineral
Quartzite
Quartzite (Primary mineral: Quartz, SiO2)
metamorphic
Quartzite (River Cobble)
Quartzite (dominant mineral: Quatrz, SiO2)
metamorphic
River Pebble (Brecciated Chert/Siltstone)
Silicon Dioxide (SiO2) with mineral inclusions
sedimentary
Sandstone
Arenite (SiO2 based with mineral cement)
sedimentary
Goldstone
Not a natural mineral or rock. It is an ornamental glass.
Manufactured Glass (Simulant)
Quartzite
Quartzite (Primary mineral: Quartz, SiO2)
metamorphic
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
mineral with metamorphic or sedimentary host
Amygdaloidal Rhyolite
Amygdaloidal felsic extrusive rock
igneous
Amygdaloidal Basalt
Amygdaloidal Basalt (Mafic volcanic rock with secondary mineral fillings)
igneous
Schist
Mica Schist
metamorphic
Pegmatite (with smoky quartz and tourmaline/biotite)
Pegmatitic Granite
igneous