Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Category
Mineral, Often A Rock Given Its Aggregate Nature
Browse mineral, often a rock given its aggregate nature specimens identified by the Rock Identifier community.
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Chrysocolla on Matrix
Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)
mineral
Agate
Cryptocrystalline quartz, SiO2
mineral
Milky Quartz with Iron Inclusions
Silicon Dioxide (SiO2)
mineral
Dyed Blue Agate
Silicon Dioxide (SiO2)
Mineral
Sandstone (Grooved/Weathered)
Arenite (composed primarily of Quartz and Lithic fragments)
sedimentary
Banded Rock (likely Quartz-rich)
Uncertain, likely a Metamorphic Rock (e.g., Gneiss or Schist) with prominent Quartz and other minerals
Mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Red and Yellow Jasper
Silicon Dioxide (SiO2)
sedimentary
Biotite Schist
Biotite Schist
Metamorphic
Pyrite in Shale
Iron Sulfide (FeS2)
mineral
Yellow Jasper
Silicon Dioxide (SiO2) with Ferric Hydroxide impurities
mineral
Red Jasper (Polished)
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Quartz
Quartz (SiO2 - Silicon Dioxide)
Mineral
Jasper
Jasper (Cryptocrystalline Quartz; SiO2)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone (Quartz Sandstone)
Arenite (primarily SiO2)
sedimentary
Jasper (specifically Yellow or Bumblebee-like Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary
Jasper (Chert)
Silicon Dioxide (SiO2)
sedimentary
Pyrite-bearing Rock / Pyrite Ore
Iron Sulfide (FeS2) in host rock matrix
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Quartz Arenite (a common type of sandstone, given the appearance), Arkose, Greywacke (depending on mineralogy)
Sedimentary Rock
Jasper
Silicon Dioxide (SiO2) with impurities, Microcrystalline Quartz
sedimentary
Pebble (likely Quartzite or Chert)
Clastic Sediment, potentially composed of SiO₂ (Quartz)
Mineral, Sediment
Jasper
Microcrystalline Quartz (SiO2) with iron oxide impurities
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Concrete Fragment
Hardened Portland Cement Composite
Anthropogenic (Man-made material mimicking sedimentary rock)
Jasper with Hematite inclusions
Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3)
sedimentary
Pumice
Pumice
igneous
Red Jasper
Jasper (variety of Chert) - SiO2
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Prehnite
Ca2Al(AlSi3O10)(OH)2 (Calcium Aluminum Silicate)
mineral
Limestone
Calcium Carbonate (CaCO3)
sedimentary
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Chert / River Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Sandstone
Arenite (primarily SiO2)
sedimentary
Bituminous Coal
Organic Sedimentary Rock (Carbon-based)
sedimentary
Red Jasper
Jasper (Silicon Dioxide with Iron Oxide impurities), formula: SiO2
mineral
Agate (specifically, multi-colored or pastel-dyed agate)
Silicon dioxide (SiO2) - specifically, a cryptocrystalline variety of quartz known as Chalcedony, with banding classified as Agate. (If it were Fluorite, the chemical formula would be Calcium Fluoride - CaF2).
Mineral
Jasper
Silicon Dioxide (SiO2) microcrystalline quartz variety
sedimentary
Pyrite in Quartz Matrix
Iron Sulfide (FeS2) embedded in Silicon Dioxide (SiO2)
mineral
Granite
Granite (a plutonic igneous rock)
Igneous