Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Sedimentary Rock (Metamorphosed)
Category
Rock (Likely Sedimentary)
Browse rock (likely sedimentary) specimens identified by the Rock Identifier community.
Drill Core Sample
Cylindrical Rock Core (Specific mineralogy varies by extraction site)
Metamorphic (Likely Gneiss or Schist based on texture)
Banded Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Mica)
metamorphic
Quartz
Quartz (SiO₂)
Mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Blue Quartzite
Quartzite (specifically a variety enriched with blue-coloring minerals)
Metamorphic Rock
Chert (or Flint)
SiO2 (predominantly microcrystalline quartz)
Sedimentary
Quartz Vein in Host Rock
Silicon Dioxide (SiO2)
mineral with metamorphic or sedimentary host
Banded Gneiss
Gneiss (High-grade metamorphic rock typically composed of Quartz, Feldspar, and Biotite/Amphiboles)
metamorphic
Quartzite
Quartzite (primarily SiO2)
Metamorphic
Yellow Jasper (within host rock)
Silicon Dioxide (SiO2) with iron hydroxides (Goethite)
sedimentary
Pyrite
Pyrite (Iron Disulfide), FeS2
Mineral
Ruby in Zoisite
Ruby (α-Al2O3) embedded in Zoisite (Ca2Al3(SiO4)3(OH)) with some Hornblende
Metamorphic Rock (composed of multiple minerals)
Banded Jasper
Silicon Dioxide (SiO2)
Mineral/Sedimentary Rock (as a cryptocrystalline variety of quartz)
Crushed Stone (Gravel/Aggregates)
Crushed rock aggregate (varied composition including Granite, Limestone, and Quartz)
sedimentary and igneous (mixed)
Quartz (Clear Quartz/Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Carnelian (Chalcedony variety)
SiO2 (Silicon Dioxide)
Mineral
Kyanite
Kyanite (Al2SiO5)
Mineral
Quartz Geode/Cluster
Quartz (SiO2)
mineral
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
Mineral
Halite
Halite (NaCl)
Mineral
Quartz (possibly milky quartz)
Quartz (Silica; SiO₂)
Mineral
Chert / Flint (a variety of Chert)
Chert (SiO2)
Sedimentary Rock (technically a microcrystalline quartz mineral aggregate)
Agate (various color varieties)
SiO₂ (Silicon Dioxide)
Mineral (specifically a variety of Chalcedony, which is a microcrystalline quartz)
Aquamarine and clear quartz
Aquamarine (Be3Al2Si6O18), Quartz (SiO2)
Mineral
Halite (Rock Salt)
Halite; NaCl (Sodium Chloride)
Mineral
Garnet (Red Garnet)
Garnet Group. The red varieties seen in jewelry are typically Almandine (Fe3Al2(SiO4)3), Pyrope (Mg3Al2(SiO4)3), or a mix of the two (pyrope-almandine series).
Mineral (specifically, a variety of the mineral species Pyrope-Almandine Garnet)
Chalcedony (Banded/Mottled Variety)
Chalcedony (a cryptocrystalline variety of Quartz, SiO2)
Mineral
Brachiopod Fossil (Spiriferid)
Phylum Brachiopoda, Order Spiriferida (CaCO3 - Calcium Carbonate)
sedimentary (fossilized organic remains)
Chert (often called Flint or River Rock)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Mineral
Fired Clay Brick (Anthropic Rock substitute)
Anthropogenic polycrystalline ceramic (predominantly Mullite and Quartz: Al6Si2O13 + SiO2)
metamorphic (man-made / anthropic)
Epidote in Quartz
Quartz with Epidote inclusions (SiO2 with Ca2(Al,Fe)3(SiO4)3(OH) inclusions)
Mineral
Banded Jasper (possibly "Picture Jasper")
Jasper (a microcrystalline variety of Quartz / Silicon Dioxide - SiO2)
Sedimentary rock (specifically a chemical sedimentary rock, or a chert if considered purely mineral aggregate)
River Rock (Basalt/Greywacke pebbles)
Fluvial gravel primarily composed of Mafic Volcanic Rock (Basalt) or Lithic Sandstone (Greywacke)
igneous and sedimentary
Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)
Silicon Dioxide (SiO2) or Mafic extrusive igneous rock
sedimentary or igneous
Banded Gneiss
Gneiss (pronounced "nice")
metamorphic
Clear Quartz (beads in a bracelet)
Quartz (SiO2)
Mineral
Pyrite
Pyrite (FeS2)
Mineral
Dyed Agate / Painted Stone
Silicon Dioxide (SiO2) with artificial pigment
sedimentary (base), then artificial
Jasper (Milky/Cream Variety)
Silicon Dioxide (SiO2) - variety of Chalcedony
sedimentary (chemical/biological)
Jasper in Basalt Matrix
Silicon Dioxide (SiO2) with impurities; Chalcedony
sedimentary (secondary mineral) within igneous