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Browse this image does not display a rock, mineral, or geological specimen. it shows a human hand wearing a ring. specimens identified by the Rock Identifier community.

Anthracite Coal

Anthracite (Carbon-rich metamorphic coal)

metamorphic

Amygdaloidal Basalt

Vesicular Basalt with secondary mineral infilling (commonly Zeolites, Calcite, or Quartz)

igneous

Stalactitic Calcite

Calcite (Calcium Carbonate, CaCO3)

mineral

Gneiss

Gneiss (High-grade metamorphic rock)

metamorphic

Grooved Maun Ball (Maul/Hammerstone-like Concretion)

Calcareous/Ferruginous Concretion in Sandstone Matrix

sedimentary

Basalt with Mineral Vein (Cobble)

Basalt (with likely Quartz/Calcite vein)

Igneous

Granite Gneiss

Gneiss (High-grade Metamorphic Rock)

metamorphic

Aquamarine

Aquamarine (Beryl variety) - Be3Al2(Si6O18)

mineral

Jasper

Silicon dioxide (SiO2) with iron oxide inclusions

sedimentary

Granite

Granite (composed primarily of Quartz SiO2, Alkali Feldspar KAlSi3O8, and Plagioclase)

igneous

Banded Agate (specifically Carnelian Agate)

Cryptocrystalline Quartz (SiO2)

mineral

Chert or Flint (polished/water-worn)

Chert (a microcrystalline or cryptocrystalline variety of quartz, SiO2). Flint is a specific variety of chert.

Sedimentary (most likely, as Chert is a sedimentary rock often found as nodules in limestone or as bedded deposits; however, it can also form by metasomatic replacement, which leans towards metamorphic processes under certain conditions)

Granite

Phaneritic Felsic Igneous Rock (Granite)

igneous

Andesite

igneous

Heulandite with Stilbite

Heulandite-Ca ((Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2O) and Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O)

mineral

Quartz (Fieldstone/Pebble)

Silicon Dioxide (SiO2)

mineral

Carnelian Agate

Chalcedony (Silicon Dioxide, SiO2) with Iron Oxide impurities

mineral

Quartz crystal with Pyrite inclusions

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

mineral

Amethyst

SiO2 (Silicon Dioxide with Iron impurities)

mineral

Granite

Granite (Phaneritic Quartz-Feldspar Igneous Rock)

igneous

Sandstone

Quartz Arenite (a type of sandstone composed of more than 90% quartz)

Sedimentary Rock

Granite

Intrusive Igneous Rock (composed primarily of Quartz: SiO2, Feldspar: KAlSi3O8, and Mica: KAl2(AlSi3O10)(OH)2)

igneous

Dendritic Jasper

Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions

sedimentary

Iron Ore / Ironstone Concretion

Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.

Mineral, specifically an iron ore