Sandstone
Arenite (composed primarily of SiO2)
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
Arenite (composed primarily of SiO2)
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz, SiO2)
Quartz
Quartz (SiO2 - Silicon Dioxide)
Amber
Succinite (Organic Gemstone)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
Shale
Shale (fine-grained clastic sedimentary rock)
Chert (Flint variety)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Sandstone
Clastic sedimentary rock (primarily SiO2)
Green Apatite on Albite
Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]
Quartz
Silicon Dioxide (SiO2)
Breciated Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2
Fish Fossil in Limestone
Lycoptera (likely) in Micritic Limestone
Chert (Flint/Chalcedony)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Sandstone (Ferruginous)
Arenite (Fe2O3 enriched)
Quartz Geode/Druzy Quartz
Quartz (SiO₂)
Ferruginous Sandstone (Ironstone)
Clastic Sedimentary Rock (composed of SiO2 with Fe2O3/FeO(OH) cement)
Sandstone
Sandstone (Sedimentary rock composed of silicate grains)
Sandstone
Sandstone (various mineral compositions)
Breccia
Clastic Breccia (General mineral composition depends on fragments, often SiO2 or CaCO3)
Tree Agate (also known as Dendritic Agate)
Silicon Dioxide with inclusions (SiO2 + Mn/Fe)
Quartz (likely macrocrystalline variety)
Quartz (SiO₂)
Asphalt Concrete
Bituminous conglomerate
Sandstone
Arenite (composed primarily of SiO2)
Sandstone
Arenite (primarily SiO2)
Lapis Lazuli
Lapis lazuli (a rock primarily composed of Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)
Quartz
Silicon Dioxide (SiO2)
Limonite (Iron Ore)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Turquoise
Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O
Bauxite
Bauxite (Al2O3·2H2O)
Peridot (Olivine)
Olivine ((Mg, Fe)2SiO4)
Agatized Petrified Wood
Silicon Dioxide (SiO2) - Chalcedony pseudomorph after Wood
Sandstone
Arenite (primarily SiO2)
Chert (and/or Flint)
Microcrystalline Quartz (SiO2)
Diamond
Diamond (C)
Precious Red Coral
Corallium rubrum / Corallium japonicum
Mixed Quartz and Jasper Pebbles
Silicon Dioxide (SiO2)
Sandstone (likely River-tumbled Picture Sandstone)
Arenite (predominantly SiO2 with iron oxide impurities)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)
Sunstone
Aventurine Feldspar ((Ca,Na)(Al,Si)4O8)
Sandstone
Arenite (SiO2 primarily)