Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Category
Browse mineral_rock specimens identified by the Rock Identifier community.
Biotite (Mica)
Biotite group (K(Mg,Fe)3AlSi3O10(F,OH)2)
Banded Sandstone (Quartzite-rich)
Clastic Sedimentary Rock (SiO2 with Iron Oxide impurities)
Clear Quartz
Quartz (Silicon Dioxide, SiO2)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Red Sandstone
Arenite (Ferruginous Sandstone)
Blue Quartzite
Quartzite with inclusions (often Dumortierite or Magnesio-riebeckite)
Basalt with Secondary Mineral Inclusions
Amygdaloidal Basalt (Mafic volcanic rock, primarily Augite and Plagioclase)
Amethyst (Agate/Chalcedony variety)
Silicon Dioxide (SiO2) with iron impurities
Almandine Garnet in Schist Matrix
Almandine - Fe3Al2(SiO4)3
Sandstone (Picture Sandstone)
Sandstone (primarily Quartz with Iron Oxide impurities)
Mica Schist
Mica Schist
Shale (with minor calcite veining)
Clastic sedimentary rock (primarily clay minerals and quartz)
Sandstone
Arenite
Agate (Polished Nodule)
Agate (Silicon Dioxide, SiO2)
Sandstone
Arenite (SiO2 principal)
Smoky Quartz
Smoky Quartz (SiO2: Silicon Dioxide)
Sandstone
Arenite (composed primarily of SiO2)
Ironstone Concretion (Moqui Marble variety)
Ferruginous Sandstone Concretion
Sandstone
Arenite (composed primarily of Quartz, SiO2)
Jasper
Cryptocrystalline Quartz (SiO2)
African Turquoise
African Turquoise (a trade name for Jasper, a variety of Chalcedony: SiO2)
Sandstone (Ferruginous)
Arenite with Iron oxide staining (SiO2 with Fe2O3)
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 principal composition)
White Chalcedony (likely Common Opal or Milky Quartz)
Silicon Dioxide (SiO2)
Tiffany Stone
Fluorite Opal (a complex mix of Fluorite, Opal, Calcite, Dolomite, Quartz, and Bertrandite)
Sandstone (Red/Brown Variety)
Arenite (SiO2 with iron oxide impurities)
Quartz with Iron Oxide Monzonite or Sandstone contact
Quartz (SiO2) with Limonite/Hematite staining
Sandstone
Arenite (SiO2 based with quartz, feldspar, or lithic fragments)
Sandstone (Pebble/Cobble)
Arenite (primarily SiO2)
Sandstone
Arenite (composed primarily of SiO2)
Sandstone
Arenite (often composed of Quartz, SiO2)
Chert / Flint
Silicon Dioxide (SiO2)
Chert (specifically Tan Chert)
Chert (SiO2)
Aventurine
Aventurine Quartz (SiO2 with inclusions)
Greenstone
Greenschist
Mahogany Obsidian
Volcanic Glass (with inclusions of Magnetite or Hematite)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Gneiss
Gneiss (High-grade regional metamorphic rock)
Green Aventurine
Silicon Dioxide (SiO2) with inclusions
Amethyst (Tumbled)
Silicon Dioxide (SiO2 with iron impurities)
Peridot (Olivine)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Granite
Granite (Felsic intrusive igneous rock)