Ferruginous Slag (Iron Smelting Byproduct)
Anthropogenic Vitreous Silicate (often containing Fayalite: Fe2SiO4)
Mineraloid/Anthropogenic (Technofossil)
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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Amber in Matrix
Succinite (Carbon-based organic polymer)
Organic (Sedimentary context)
Limonite (Hydrated Iron Oxide / Bog Iron)
FeO(OH)·nH2O
Mineral (Sedimentary context)
Eroded Brick or Pumice-like Scoria
Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)
igneous
Quartz (Clear/Smoky Geode fragment)
Silicon Dioxide (SiO2)
mineral
Green Agate
Cryptocrystalline Quartz (SiO2)
mineral
Chalcedony (specifically Agate or Flint)
Silicon Dioxide (SiO₂)
Mineral
Sandstone with Manganese Dendrites
Arenite (mostly SiO2) with Manganese Oxide inclusions (MnO2)
sedimentary
Celestite (Celestine) Druze on Agate/Host Rock
Strontium sulfate (SrSO4)
mineral
Satin Spar (often marketed as Selenite)
Fibrous Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O
mineral
Milky or Iron-Stained Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Amethyst
Amethyst (Silicon Dioxide, SiO2)
mineral
Quartz (Vein Quartz)
Silicon Dioxide (SiO2)
mineral
Agate (specifically Lace Agate or Banded Agate)
Silicon Dioxide (SiO2)
mineral
Tiger's Eye (often misinterpreted as Gold Ore in this context)
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Chert (often called Flint in this context)
Silicon Dioxide (SiO2)
sedimentary
Desert Rose
Gypsum (variety Selenite) - CaSO4·2H2O
mineral
Amethyst Geodes
Silicon Dioxide (Quartz with Iron impurities), SiO2
mineral
Slag (Anthropogenic Glass/Iron byproduct)
Ferro-silicate Slag
Anthropogenic (Man-made)
Amethyst Stalactite Slice
Crystalline Quartz (SiO2) with trace Iron (Fe4+)
mineral
Red Agate
Agate (Cryptocrystalline variety of Quartz, SiO2)
mineral
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
mineral
Orbicular Jasper (Ocean Jasper)
Silicon Dioxide (SiO2) with iron and magnesium inclusions
mineral
Banded Agate (Dyed Purple)
Agate (Variety of Chalcedony/Quartz), SiO2
mineral
Quartz (Milky/Crystalline fragment)
Silicon Dioxide (SiO2)
mineral
Onyx Marble (Banded Calcite)
Calcite (Calcium Carbonate, CaCO3)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Blue Calcite
Calcium Carbonate (CaCO3)
mineral
Carnelian
Carnelian (variety of Chalcedony, SiO2)
mineral
Blue Lace Agate (Banded Chalcedony)
Silicon Dioxide (SiO₂)
mineral
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
mineral
Onyx Marble (also commonly called Onyx)
Calcite (CaCO3), often with other mineral impurities
Sedimentary Rock (specifically a type of Travertine)
Rough Quartz Crystal in Matrix
Silicon Dioxide (SiO2)
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Greenstone with Epidote or Quartz veins
Metabasalt (Greenstone facies)
metamorphic
Chert / Flint
Cryptocrystalline quartz (SiO2)
Sedimentary
Chrysocolla
Hydrated copper phyllosilicate (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Geode (Calcite or Quartz)
Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)
sedimentary
Chrysocolla
Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O)
mineral
Agate (specifically Waterline or Onyx-type Agate)
Silicon Dioxide (SiO2) - variety Chalcedony
mineral
Quartz Druze on Matrix
Silicon Dioxide (SiO2)
mineral