Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Category
Browse the purple specimen is a mineral (amethyst); the white specimen is a sedimentary rock (limestone or marble). specimens identified by the Rock Identifier community.
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Chert (Gravel)
Microcrystalline Quartz (SiO2)
Quartz Mica Schist
Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Sandstone (Quartzose Pebble)
Clastic sedimentary rock (primarily SiO2)
Sedimentary Sandstone (Sandstone Slab)
Arenite (SiO2 with Fe2O3 staining)
Lapis Lazuli (Low-grade/Calcite-heavy)
Na8[Al6Si6O24]n(S,Cl,SO4,OH)2 (Lazurite component)
Amethyst
Quartz (Silicon Dioxide, SiO2) with iron impurities
Sodalite
Na8(Al6Si6O24)Cl2 (Sodalite)
Shale or Slate with Quartz Veins
Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins
Lapis Lazuli
Lapis Lazuli (a rock composed primarily of Lazurite, Sodalite, Calcite, and Pyrite)
Chert
Chert (microcrystalline quartz, SiO2)
Sandstone (Ferruginous)
Arenite with Iron Oxides
Fossil Shark Tooth (Cretaceous white shark type)
Squalicorax (commonly known as Crow Shark)
Orange Calcite
Calcium Carbonate (CaCO3)
Sandstone
Clastic sedimentary rock (primarily Quartz and Feldspar)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with Iron impurities)
Amethyst
Amethyst (Silicon Dioxide - SiO2 with Iron impurities)
Sandstone (likely Graywacke or Arkose variant)
Clastic Sedimentary Rock (Lithic Sandstone)
Moqui Marble (Ironstone Concretion)
Iron Oxide Concretion (Fe2O3 / FeO(OH))
Quartzite
Quartzite (SiO2)
Pink Opal
Amorphous Hydrous Silica (SiO2·nH2O)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Sandstone (Weathered Pebble)
Arenite (primarily SiO2)
Sandstone
Arenite (SiO2-rich)
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
Chert (specifically Jasper or Flint)
Cryptocrystalline Quartz (SiO2)
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Lapis Lazuli
Lapis lazuli (primary mineral: Lazurite, (Na,Ca)8(AlSiO4)6(S,Cl,SO4,OH)2)
Sandstone (Green/Yellow Siltstone variant)
Arenite or Siltstone (primarily SiO2 with mineral staining)
Quartz / Rock Crystal
Silicon Dioxide (SiO2)
Herkimer Diamond (Quartz Crystal)
Silicon Dioxide (SiO2)
Quartz in Matrix (possibly Basalt or Siltstone host)
Silicon Dioxide (SiO2) in Host Rock
Sandstone (River Cobble)
Clastic sedimentary rock (primarily SiO2 with various lithic fragments)
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Citrine Quartz
Citrine (Silicon Dioxide, SiO2)
Chert (Jasper/Limonitic Chert)
Microcrystalline Quartz (SiO2)
Citrine
Silicon dioxide (SiO2)
Sandstone (Quartzose)
Arenite (SiO2 principal)
Sandstone (Iron-stained)
Clastic sedimentary rock (SiO2 with Fe2O3 staining)
Amethyst
Amethyst (Silicon Dioxide with iron impurities), SiO2
Sandstone (likely Arkose)
Arenite (composed mainly of SiO2 with Feldspar)