Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Category
Mineral Precipitate (Anthropogenic Context)
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Banded Agate
Agate (Cryptocrystalline variety of Quartz, SiO2)
mineral
Orange Calcite (Banded Calcite)
Calcium Carbonate (CaCO3)
mineral
Weathered Volcanic Rock (possibly Rhyolite or Andesite Pebble)
Volcanic rock (e.g., Rhyolite or Andesite, specific identification would require thin section analysis or chemical assay). Mineral composition: Primarily feldspars (orthoclase and/or plagioclase), quartz (in rhyolite), micas, amphiboles, and sometimes pyroxenes.
Igneous, specifically volcanic/extrusive (possibly Rhyolite or Andesite)
Oolitic Limestone (Oolite)
Oolitic Limestone (primarily Calcium Carbonate, CaCO3)
sedimentary
Blue Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Yellow Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Geode (Smoky Quartz)
Silicon Dioxide (SiO2)
mineral
Quartz Geode (River Cobble)
Silicon Dioxide (SiO2)
mineral
Amethyst (Tumbled Chips)
Amethyst (Silicon Dioxide with Iron impurities, SiO2)
mineral
Geode (Unbroken)
Silicon Dioxide (SiO2) usually as Microcrystalline Quartz or Chalcedony
sedimentary
Common Opal
Hydrated Amorphous Silica (SiO2·nH2O)
mineraloid
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Moss Agate
Silicon Dioxide with inclusions (SiO2)
mineral
Limestone (specifically Fossiliferous or Crinoidal Limestone)
Calcium Carbonate (CaCO3) - Calcite Rock
sedimentary
Chrysocolla
Hydrated copper silicate - Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O
mineral
Fluorite (Polished Point/Tower)
Calcium Fluoride (CaF2)
mineral
Chert (Quartzite-rich River Pebble)
Silicon Dioxide (SiO2)
sedimentary
Red Jasper
Jasper (SiO2, Silicon Dioxide with Iron inclusions)
sedimentary
Chert (Common Variety, Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Mineral
Asphalt (Road Aggregate)
Bituminous Conglomerate / Asphalt Concrete
Anthropogenic (Man-made)
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Chert (Jasper or Flint variant)
Chert (composed of microcrystalline quartz, SiO2)
sedimentary
Moss Agate
Silicon Dioxide (SiO2) with Chlorite/Oxide inclusions
mineral
Rough Green Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Quartz in Matrix (possibly Basalt or Siltstone host)
Silicon Dioxide (SiO2) in Host Rock
mineral
Sandstone (likely River-tumbled Picture Sandstone)
Arenite (predominantly SiO2 with iron oxide impurities)
sedimentary
Hematite (Iron Ore)
Hematite (Fe2O3)
mineral
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)
mineral
Sandstone (with manganese staining)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (Fe-rich SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) in Host Rock
sedimentary
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Green Calcite
Calcium Carbonate (CaCO3)
mineral
Blue Goldstone
Aventurine Glass (Silicon Dioxide infused with Cobalt/Copper)
Synthetic (Man-made Glass)
Quartz (Clear / Rock Crystal)
Silicon Dioxide (SiO2)
Mineral
Quartz Geode (Water-worn)
Silicon Dioxide (SiO2)
mineral
Opal
Hydrated Silica (SiO2·nH2O)
mineral
Chert Pebble
Microcrystalline Quartz (SiO2)
sedimentary
Quartz-veined Siltstone/Greywacke
Clastic Sedimentary Rock with Quartz Infill (SiO2 vein)
sedimentary