Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')
Calcite (Calcium Carbonate, CaCO3)
Category
Browse mineral and sedimentary specimens identified by the Rock Identifier community.
Banded Calcite (often sold as 'Mexican Onyx' or 'Calcite Onyx')
Calcite (Calcium Carbonate, CaCO3)
Quartz Geode Fragment
Silicon Dioxide (SiO2) in a Sedimentary Host
Marble
Recrystallized Calcite (CaCO3) / Marble
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
Red Sandstone
Arenite (primarily composed of SiO2 with Fe2O3 cement)
River Quartzite Siltstone
Quartz-rich Meta-siltstone (SiO2 dominated)
Gneiss
Gneiss (High-grade metamorphic rock)
Quartz (Clear / Rock Crystal)
Silicon Dioxide (SiO2)
Shale
Fissile Mudstone (primarily composed of phyllosilicate minerals like kaolinite, montmorillonite, and illite)
Sandstone (Water-worn)
Arenite
Fluorite
Calcium Fluoride (CaF2)
Fluorite
Fluorite (CaF₂)
Sandstone
Arenite (Siliclastic sedimentary rock)
Orthoclase Feldspar
Potassium aluminum silicate (KAlSi3O8)
Green Calcite
Calcium Carbonate (CaCO3)
Amethyst (Geode/Druzy)
Silicon Dioxide (SiO2) with iron impurities
Green Aventurine
Silicon dioxide (SiO2) with fuchsite inclusions
Sandstone with Manganese Dendrites/Oxide coatings
Arenite with Pyrolusite and Romanechite (MnO2)
Jasper
Silicon Dioxide (SiO2)
Kyanite
Kyanite (Al2SiO5)
Pyrite
Iron Sulfide (FeS2)
Pyrite and Sunstone
Iron Sulfide (FeS2) and Plagioclase Feldspar ((Ca,Na)Al(Al,Si)Si2O8)
Carnelian
Carnelian (SiO2)
Chalcedony (Agate/Carnelian type)
Silicon Dioxide (SiO2)
Gneiss
Gneiss
Quartz (Chert/Chunky Chalcedony)
Silicon Dioxide (SiO2)
Fluorite
Calcium Fluoride (CaF2)
Potassium Feldspar and Quartz
KAlSi3O8 (Potassium Feldspar) and SiO2 (Quartz)
Carnelian and White Quartz Bracelet
Silicon Dioxide (SiO2) - specifically Carnelian (Chalcedony) and Rock Crystal/Snow Quartz
Sandstone (Micaceous)
Arenite (composed primarily of SiO2)
Sandstone
Arenite (primarily SiO2)
Sandstone (Ferruginous)
Arenite with Iron-Oxide Cement
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Sandstone
Arenite (primarily SiO2)
Sandstone (with garnet granules)
Clastic sedimentary rock (primarily SiO2 with Fe3Al2(SiO4)3 inclusions)
Fossilized Dinosaur Skull (Tyrannosaurus rex)
Tyrannosaurus rex (permineralized fossil), rich in Hydroxylapatite/Silica
Dinosaur Fossil (Tyrannosaurus rex skull replica/specimen)
Tyrannosaurus rex (fossilized in permineralized sedimentary matrix)
Jasper
Silicon dioxide (SiO2)
Sandstone
Arenite (primarily SiO2)
Pyrite
Pyrite (FeS2)
Gypsum (Wallboard/Drywall)
Calcium Sulfate Dihydrate (CaSO4·2H2O)