Limestone
Calcium Carbonate (CaCO3)
Category
Browse antropogenic (man made glass byproduct) specimens identified by the Rock Identifier community.
Limestone
Calcium Carbonate (CaCO3)
Granite Cobble
Felsic Intrusive Igneous Rock (composed of Quartz, Alkali Feldspar, and Plagioclase)
Sandstone (Ferruginous)
Arenite (Fe2O3 rich)
Milky Quartz
Silicon dioxide (SiO2)
Polished flint/chert pebble
Microcrystalline quartz (SiO₂), commonly called chert or flint
Chert (Chalk-associated Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Granite
Granite (Felsic Plutonic Rock)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Granite
Granite (Phaneritic Quartz-Feldspar Rock)
Milky Quartz Geode Fragment
Silicon Dioxide (SiO2)
White Quartz
Quartz (SiO2)
Weathered dark flint (chert) pebble
Microcrystalline quartz (SiO₂), commonly called flint or chert
Banded Black Onyx (Chalcedony)
Silicon Dioxide (SiO₂)
Quartz
Silicon Dioxide (SiO2)
Chert (also known as Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
Carnelian
Chalcedony (Silicon Dioxide, SiO2 with Iron Oxide impurities)
Weathered green-gray stone, likely serpentinite or chlorite-rich metamorphic rock
Probable serpentinite (antigorite–lizardite), possibly chlorite schist or altered basalt
Clear quartz sphere or polished quartz cabochon (tentative)
Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone
Tumbled serpentine (likely)
Serpentine-group minerals, commonly antigorite or lizardite; approximate formula Mg₃Si₂O₅(OH)₄
Weathered granitic rock
Granite or granodiorite; primarily quartz (SiO₂), feldspar, and mica
Queen Conch Shell (Biogenic Calcium Carbonate)
Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)
Sandstone (River Cobble)
Clastic sedimentary rock (primarily SiO2 with various lithic fragments)
Ferruginous Sandstone
Sandstone, Iron-rich
Nephrite Jade
Tremolite-Actinolite solid solution Ca2(Mg,Fe)5Si8O22(OH)2
Likely serpentine pebble
Serpentinite; predominantly serpentine-group minerals, Mg₃Si₂O₅(OH)₄
Quartz (likely Milky Quartz)
Quartz (SiO₂ - Silicon Dioxide)
Quartzite (Iron-stained)
Quartzite (SiO2 with iron oxides)
Clear quartz crystal
Quartz (silicon dioxide, SiO₂)
Ferrocoke or Slag
Anthropogenic pyrometallurgical residue
Granite
Granite (Mainly Quartz SiO2, K-Feldspar KAlSi3O8, and Plagioclase)
Sandstone (Ferruginous)
Arenite (with Iron Oxide cement)
Chert
Microcrystalline Quartz (SiO2)
Granite
Phaneritic Felsic Igneous Rock
Diamond (Cut Gemstone)
Carbon (C)
Sandstone (likely Fossiliferous)
Arenite / Sedimentum arenaceum
Tumbled serpentinite (likely antigorite-rich serpentine)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, or brucite
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
Granite
Phaneritic Igneous Rock (primarily Quartz, Feldspar, and Mica)
Sandstone Chert/Quartzite
Silicon Dioxide (SiO2) - Sedimentary Sandstone / Orthoquartzite
Quartz
Quartz (SiO₂ - Silicon Dioxide)
Gypsum (Satin Spar / Alabaster variety)
Calcium Sulfate Dihydrate (CaSO4·2H2O)