Sand Grain (Silica/Quartz Grain)
Silicon Dioxide (SiO2)
Category
Browse industrial byproduct (often confused with igneous rocks or meteorites) specimens identified by the Rock Identifier community.
Sand Grain (Silica/Quartz Grain)
Silicon Dioxide (SiO2)
Amethyst
Quartz (SiO2) variety
Sapphire Rough (Corundum)
Corundum (Aluminum Oxide, Al2O3)
Agate / Banded Chalcedony
Agate (Silicon Dioxide / SiO2)
Raw Ruby (Corundum)
Corundum (Aluminum Oxide, Al2O3)
Quartz Pebble
Silicon Dioxide (SiO2)
Rose Quartz
Silicon Dioxide (SiO2)
Garnet (Almandine/Pyrope variety)
Silicate mineral group; typically Fe3Al2(SiO4)3 (Almandine) or Mg3Al2(SiO4)3 (Pyrope)
Serpentine
Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Fe)2O5(OH)4)
Basalt with Secondary Mineralization (Likely Zeolites or Calcite)
Aphanitic mafic volcanic rock with secondary mineral inclusions (e.g., CaAl2Si3O10·3H2O for Scolecite)
Quartzite Pebble
Quartzite (SiO2)
Black Tourmaline
Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)4)
Rubellite Tourmaline
Elbaite Tourmaline, Na(Li1.5Al1.5)Al6(Si6O18)(BO3)3(OH)3(OH)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
André Landed Here Rock (Glacial Erratic)
Granodiorite / Diorite (compositional estimate)
Mica Schist
Schist (Muscovite/Biotite Schist)
Rhodonite
Manganese Inosilicate (MnSiO3)
Magnetite (potentially Hematite)
Magnetite (Fe₃O₄)
Sodalite
Sodalite - Na8(Al6Si6O24)Cl2
Blue Sapphire (faceted in jewelry)
Corundum (Al2O3)
Milky Quartz
Silicon Dioxide (SiO2)
Prehnite
Prehnite (Ca2Al(AlSi3O10)(OH)2)
Red Garnet
Pyrope-Almandine series (Mg3Al2(SiO4)3 to Fe3Al2(SiO4)3)
Gold-bearing Quartz Ore
Auriferous Quartz (SiO2 + Au)
Schist
Mica Schist (formula variable based on mineral content, typically containing [K,Al,Fe,Mg,Si,O,H])
Painted Sandstone Cobble
Clastic Sedimentary Rock (Sandstone base)
Rough Quartz (var. Citrine or Yellow Quartz)
Silicon Dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Sapphire
Corundum (Al2O3)
Pyrite
Iron sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Quartz (Gray or Smoky variety)
Silicon Dioxide (SiO2)
Quartz Pebble
Silicon Dioxide (SiO2)
Garnet in Host Rock
Garnet Group (A3B2(SiO4)3)
Botryoidal Quartz
Silicon Dioxide (SiO2)
Granite Glacial Erratic
Granite (Phaneritic Quartz-Feldspar Plutonic Rock)
Pink Thulite
Thulite (Ca2Al3(SiO4)3(OH)) - Pink Zoisite
Quartz Vein in Host Rock
Silicon Dioxide (SiO2) in matrix
Muscovite Mica
Muscovite (KAl2(AlSi3O10)(OH)2)
Zoisite with Hornblende
Zoisite (Ca2Al3(SiO4)3(OH)) with Amphibole inclusions
Black Tourmaline (Schorl)
Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)
Hematite
Hematite (Iron(III) oxide, Fe2O3)