Gneiss
Gneiss (High-grade metamorphic rock composed primarily of Quartz, Feldspar, and various Micas)
Category
Browse sedimentary mineral specimens identified by the Rock Identifier community.
Gneiss
Gneiss (High-grade metamorphic rock composed primarily of Quartz, Feldspar, and various Micas)
Black Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Druzzy Quartz on Matrix
Silicon Dioxide (SiO2)
River Stone (likely Mudstone or Siltstone)
Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)
Sandy Ironstone
Ferruginous Sandstone
Quartz Geode
Silicon Dioxide (SiO2)
Blue Celestite (with Galena)
Strontium sulfate (SrSO4) and Lead sulfide (PbS)
Chert (and/or Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Sandstone (Micaceous/Feldspathic variant)
Arenite (specifically subarkose or lithic arenite)
Sandstone
Arenite
Clear Quartz Cluster
Silicon Dioxide (SiO2)
Clear Quartz Crystal Cluster
Silicon Dioxide (SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Pyrite in Matrix (Commonly called Fool's Gold)
Iron Sulfide (FeS2)
Galena
Lead(II) sulfide (PbS)
Quartz
Silicon Dioxide (SiO₂)
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Pyrite
Iron Disulfide (FeS2)
Fluorite (Rainbow Fluorite)
Calcium Fluoride (CaF2)
Botryoidal Chalcedony (likely Desert Rose/Agatized Geode Crust)
Silicon Dioxide (SiO2)
Banded Agate
Cryptocrystalline Quartz (SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO₂)
Turquoise
CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminium phosphate)
Pyrite
Iron Sulfide (FeS2)
Quartz (Milky/Smoky variety)
Silicon Dioxide (SiO2)
Rough Garnet (Almandine)
Almandine Garnet (Fe3Al2(SiO4)3)
Hematite
Iron(III) oxide (Fe2O3)
Moss Agate
Silicon Dioxide (SiO2) with inclusions of manganese or iron oxide
Quartz
Silicon Dioxide (SiO2)
Satin Spar (Selenite)
Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
Common Opal in Host Rock
Hydrated Silica (SiO2·nH2O)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Arenite (SiO2 based)
Asphalt Concrete (Bituminous Conglomerate)
Anthropogenic Bituminous Conglomerate
Red Sandstone
Arenite (Ferruginous Sandstone)
Petrified Wood
Silicified Wood (SiO2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Sandstone (Picture Sandstone)
Sandstone (primarily Quartz with Iron Oxide impurities)
Blue Lace Agate
Silicon Dioxide (SiO₂)
Jasper with Quartz inclusions
Silicon Dioxide (SiO2)
Oolitic Limestone
Oolite (Sedimentary rock composed of CaCO3)
Chert / Flint
Silicon Dioxide (SiO2)