Tumbled Quartz (Peach Quartz / Red Quartz)
Silicon Dioxide (SiO2)
mineral
Category
Mineral Precipitate (Anthropogenic Context)
Browse mineral precipitate (anthropogenic context) specimens identified by the Rock Identifier community.
Learn about Mineral Precipitate (Anthropogenic Context) in the encyclopedia
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Vein-filled Sedimentary Rock
Silicified sedimentary rock with quartz/calcite vein
sedimentary
Dark mafic rock, likely basalt or amphibolite
Probable basalt (plagioclase feldspar + pyroxene ± olivine); definitive identification requires a fresh surface or thin section
igneous
Eroded Brick or Pumice-like Scoria
Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)
igneous
Marcasite on Agate / Sphalerite-Pyrite Agate Geode Slice
Marcasite (FeS2) / Pyrite on Quartz (SiO2)
mineral
Hematite
Hematite, Iron(III) oxide (Fe2O3)
mineral
Pyrite
Pyrite (FeS₂)
Mineral
Sandstone
Arenite (Sedimentary Rock)
sedimentary
Pyrite in Quartz
Iron Sulfide (FeS2) embedded in Silicon Dioxide (SiO2)
mineral
Fluorite (Fluorescent)
Calcium Fluoride (CaF2)
mineral
Chert (often called Flint in this context)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Ferrochrome Slag
Calcium-Aluminium-Magnesium Silicate Slag
industrial byproduct
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
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
Banded Agate
Silicon Dioxide (SiO2) - Chalcedony
mineral
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Quartz Vein in Host Rock
Silicon dioxide (SiO2) veins in metamorphic/igneous host rock
igneous
Limonite
FeO(OH)·nH2O
mineral
Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Ironstone / iron-oxide-rich rock fragment
Likely limonite/goethite-rich ironstone; exact identification is not possible from the image alone
sedimentary
Jasper / Chert (polished)
Microcrystalline Quartz (SiO2)
sedimentary / mineral
Likely flint/chert fragments
Microcrystalline quartz (SiO₂), possibly fossil-bearing chert
sedimentary
Agate Geode
Silicon dioxide (SiO2) - Chalcedony
mineral
Fluorite
Fluorite (Calcium Fluoride - CaF2)
mineral
Blue Aragonite (polished)
Aragonite (CaCO3)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Hematite
Iron(III) oxide (Fe2O3)
mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Sandstone (Banded)
Arenite with Iron Oxide Banding
sedimentary
Quartz
Quartz (SiO2)
Mineral
Goethite/Hematite Nodule
Goethite (FeO(OH)) and Hematite (Fe2O3)
mineral
Limonite (Iron Ore)
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
mineral
Ferruginous Slag (Iron Smelting Byproduct)
Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)
Mineraloid/Anthropogenic (Technofossil)
Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Flint or chert
Microcrystalline quartz (SiO₂), commonly chalcedony with possible impurities
sedimentary
Quartz Geode
Crystalline Silicon Dioxide (SiO2)
mineral
Limonite Concretion
Hydrated Iron Oxide-Hydroxide, FeO(OH)·nH2O
mineral
Limonite (Iron Ore)
Goethite and related iron hydroxides (FeO(OH)·nH2O)
mineral
Copper-bearing Quartz (likely Malachite on Quartz matrix)
Cu2CO3(OH)2 (Malachite) on SiO2 (Quartz)
mineral