Quartz-veined Siltstone
Siltstone with Quartz (SiO2) veins
sedimentary
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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Amygdaloidal Basalt
Amygdaloidal Basalt (containing secondary minerals like Quartz, Zeolites, or Calcite)
igneous
Banded Iron Formation (BIF)
Banded Iron Formation (Fe2O3 + SiO2)
sedimentary
Common Opal
Hydrated silica (SiO2 " nH2O)
mineral
Quartz Geode (with Agate banding)
Silicon Dioxide (SiO2)
Sedimentary or Igneous (secondary formation)
Ceramic or Polished Stone Heart (Anthropogenic Material)
Glazed Ceramic (Silicon Dioxide based coating on Alumina Silicate body) or Polished Limestone/Marble (Calcium Carbonate, CaCO3)
Synthetic/Anthropogenic Mineraloid
Fossiliferous Limestone
Sedimentary rock containing Indeterminate Fossil remains (likely Crinoid stem or Bryozoan fragment)
fossil
Lake Superior Agate
Chalcedony (Silicon Dioxide, SiO2) with Iron impurities
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Boulder Opal
Hydrated Silica (SiO2·nH2O)
mineraloid
Petrified Wood
Silicified Wood (SiO2 - primarily Quartz/Chalcedony/Opal)
Mineral/Fossil (Sedimentary context)
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Ferrochrome Slag
Anthropogenic silicate/oxide glass (Complex silicate matrix with Cr-Fe-Si inclusions)
Industrial byproduct (often confused with igneous rocks or meteorites)
Blue Goldstone
Goldstone (artificial glass)
Mineral (man-made glass, not natural)
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
mineral
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
mineral
Thunderegg
Agate-filled Rhyolitic Nodule (SiO2)
mineral
Orange Calcite
Calcium Carbonate (CaCO3)
mineral
Quartz Vein / Milky Quartz
Silicon Dioxide (SiO2)
mineral
Bloodstone (Heliotrope)
Silicon Dioxide (SiO2) - Variety of Chalcedony/Jasper
mineral
Carnelian
Carnelian Chalcedony (SiO2)
mineral
Chert (often called Flint in archaeological contexts)
Silicon Dioxide (SiO2)
sedimentary
Quartz
Silicon Dioxide (SiO2)
mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Sandstone with Liesegang Rings
Arenite with Iron Oxide Liesegang Banding
sedimentary
Quartzite with vugs/druzy quartz
Crystalline Silicon Dioxide (SiO2)
metamorphic
Granite (likely a river or beach pebble)
Granite (a felsic intrusive igneous rock primarily composed of quartz, feldspar, and mica)
Igneous
Septarian Nodule (Galt)
Calcareous concretion / Septarian concretion
sedimentary
Jasper with Quartz Druzy
Silicon Dioxide (SiO2)
sedimentary
Ferruginous Sandstone (Grit)
Clastic Sedimentary (Ironstone-rich Sandstone)
sedimentary
Iron Ore (Hematite/Magnetite mixture)
Ferrous Oxide (Fe2O3 / Fe3O4)
sedimentary
Quartz Geode Fragment
Silicon Dioxide (SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO₂)
mineral
Clear Quartz (or Rock Crystal)
Quartz (SiO₂)
Mineral
Agate (specifically Carnelian Agate or Lake Superior style Agate)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
mineral
Dyed Quartz Geode
Silicon Dioxide (SiO2) with artificial pigment
mineral
Asphalt Concrete (Bituminous Pavement)
Aggregates in Bitumen Matrix
Technogenic / Anthropogenic Pavement Material
River Pebble (Greywacke or Chert mix)
Silicon Dioxide (SiO2) with varying mineral impurities
sedimentary
Dolomite
Dolomite (CaMg(CO3)2)
Mineral
Jasper (Iron-stained Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Chert / Chalcedony Nodules
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary