Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Sandstone (Ferruginous)
Arenite (Fe-bearing Clastic Sedimentary Rock)
Turquoise
Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O
Sodalite
Na8(Al6Si6O24)Cl2
Diamond
Native Carbon (C)
Orthoclase Feldspar
Potassium Aluminum Silicate (KAlSi3O8)
Quartz
Quartz (SiO₂)
Diamond
Diamond (carbon allotrope), C (chemical formula)
Banded Calcite (often sold as 'Travertine' or 'Mexican Onyx')
Calcium Carbonate (CaCO3)
Banded Gneiss
Gneiss (High-grade regional metamorphic rock)
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide inclusions - SiO2)
Amethyst (as a jewelry accent)
Amethyst (Silicon Dioxide SiO2 with Iron impurities)
Graphite
Graphite (Carbon, C)
Ironstone with Limonite/Goethite coating
Ferruginous Sedimentary Rock (contains Limonite FeO(OH)·nH2O)
Quartz (Milky/Clear Quartz)
Silicon Dioxide (SiO2)
Mica Schist
Foliated Metamorphic Rock (rich in Muscovite or Biotite)
Amethyst
Crystalline Quartz (SiO2) with iron impurities
Turquoise
Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Green Fluorite in Host Rock
Fluorite (Calcium Fluoride, CaF2)
Clear Quartz
Silicon Dioxide (SiO2)
Amethyst
Amethyst (Silicon Dioxide, SiO2)
Sandstone
Sandstone (arenite is a more specific geological term for a clean sandstone, while wacke refers to a dirty sandstone with significant matrix)
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O)
Quartz (with iron oxide staining)
Silicon Dioxide (SiO2)
Agate
Silicon Dioxide (SiO2) - variety: Chalcedony
Conglomerate
Conglomerate (Detrital sedimentary rock)
Chert Pebble (Jasper variety)
Microcrystalline Quartz (SiO2)
Diamond (Cut jewelry specimen)
Diamond (pure Carbon, C)
Sedimentary Breccia
Breccia (Clastic Sedimentary Rock)
Clear Quartz
Silicon Dioxide (SiO2)
Quartz (River Pebble)
Silicon Dioxide (SiO2)
Tiger's Eye (Unpolished)
Pseudomorph of Quartz after Crocidolite (SiO2)
Almandine Garnet in Schist
Almandine, Fe3Al2(SiO4)3
Dark-colored Igneous Rock (likely Basalt or Diabase)
Basalt (extrusive igneous) or Diabase (intrusive igneous)
Milky Quartz (Water-worn Pebble)
Silicon Dioxide (SiO2)
Quartz Geode / Druzy Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Shale (with Iron Oxide staining)
Fissile Mudstone (primarily Quartz and Clay minerals)
Milky Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Green Aventurine
Silicon Dioxide (SiO2) with inclusions
Amethyst
Silicon dioxide with iron impurities (SiO2)
Carnelian
Carnelian (SiO2)
Olivine in Basalt (Peridot)
Magnesium Iron Silicate (Mg,Fe)2SiO4 (Mineral) within Basalt (Rock)