Chert (Arrowhead Debitage or Flake)
Microcrystalline silica (SiO2)
sedimentary
Category
Mineral Precipitate (Anthropogenic Context)
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
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Weathered iron-rich rock, likely basalt or ironstone
Probable weathered basalt (mafic silicate rock); exact identification requires a fresh surface and testing
igneous
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite
mineral
Limonite/Ironstone
Limonite (FeO(OH)·nH2O)
mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
Mineral
Basalt
Basalt (Mafic Extrusive Igneous Rock)
igneous
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Fluorite
Fluorite (Calcium Fluoride - CaF2)
mineral
Quartz Geode
Silicon Dioxide (SiO2) in a sedimentary host
sedimentary
Vein-filled Sedimentary Rock
Silicified sedimentary rock with quartz/calcite vein
sedimentary
Chert (Nodule)
Chert (variety of microcrystalline quartz, SiO2)
sedimentary
Gold in Quartz Matrix
Native Gold (Au) with Quartz (SiO2)
mineral
Banded Carnelian Agate
Silicon Dioxide (SiO2)
sedimentary
Carnelian
Chalcedony (SiO₂)
mineral
Sandstone
Arenite (Sedimentary Rock)
sedimentary
Seraphinite
Clinochlore (Mg,Fe)5Al(AlSi3O10)(OH)8 - specific variety for Seraphinite due to its fibrous inclusions and chatoyancy.
Mineral
Arsenopyrite in Quartz Matrix
Arsenopyrite (FeAsS) with Quartz (SiO2)
Mineral in a Metamorphic/Hydrothermal rock
Jasper (Red Jasper)
Silicon Dioxide (SiO₂)
sedimentary
Yellow Quartz
Silicon Dioxide (SiO2)
mineral
Tumbled Quartz (Peach Quartz / Red Quartz)
Silicon Dioxide (SiO2)
mineral
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Greenstone Celt (Polished Stone Axe)
Metamorphosed mafic rock (often Basalt or Diabase)
metamorphic
Banded Agate
Silicon Dioxide (SiO2) - Chalcedony
mineral
Slag
Anthropogenic Vitreous Silicate / Ferro-silicate Slag
igneous
Ferrochrome Slag
Calcium-Aluminium-Magnesium Silicate Slag
industrial byproduct
Marcasite on Agate / Sphalerite-Pyrite Agate Geode Slice
Marcasite (FeS2) / Pyrite on Quartz (SiO2)
mineral
Tumbled Hematite
Iron(III) oxide (Fe2O3)
mineral
Orange Calcite
Calcite (Calcium Carbonate, CaCO3)
mineral
Ferruginous Slag (Iron Smelting Byproduct)
Fused Silicate Scoria (Amorphous mixture of FeO, SiO2, and CaO)
Antropogenic Glass / Mineraloid
Kidney Stone (Urolith / Calcium Oxalate Stone)
Calcium Oxalate Monohydrate (Whewellite) / Calcium Oxalate Dihydrate (Weddellite)
mineral
Pyrite in Quartz
Iron Sulfide (FeS2) embedded in Silicon Dioxide (SiO2)
mineral
Quartz Vein in Host Rock
Silicon dioxide (SiO2) veins in metamorphic/igneous host rock
igneous
Opalite
Synthetic Glass, SiO2 base with metallic inclusions
mineraloid (synthetic)
Hematite
Hematite, Iron(III) oxide (Fe2O3)
mineral
Sandstone (Banded)
Arenite with Iron Oxide Banding
sedimentary
Baroque Pearl
Calcium Carbonate (Aragonite or Calcite) and Conchiolin
Organic Gemstone
Banded Chert (Jasper)
Silicon Dioxide (SiO2)
sedimentary
Chalcedony (Milky Agate/Quartz)
Silicon Dioxide (SiO2)
mineral
Gold-Bearing Quartz
Silicon Dioxide with Native Gold (SiO2 + Au)
mineral
Yellow Ochre / Limonite
Limonite (FeO(OH)·nH2O)
Mineral
Hematite
Iron(III) oxide (Fe2O3)
mineral
Chert (Smoky variety)
Microcrystalline Quartz (SiO2)
sedimentary