Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Category
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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.
Limonite (Iron Ore/Hydrated Iron Oxide)
Limonite (mixture of FeO(OH)·nH₂O minerals, mainly Goethite, FeO(OH) and Lepidocrocite, FeO(OH))
Mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Granite (Pink/Potassium-rich)
Phaneritic Plutonic Felsic Igneous Rock (primarily SiO2 with KAlSi3O8)
igneous
Baroque Pearl (and potentially a small Sapphire/Blue Topaz)
Pearl: Calcium Carbonate (aragonite or calcite) with conchiolin. Sapphire: Aluminum Oxide (Al2O3). Blue Topaz: Al2SiO4(F,OH)2.
Organic Gemstone (for pearl), Mineral (for sapphire/topaz)
Yellow Quartz (Chalcedony/Agate)
Silicon Dioxide (SiO2)
Mineral
Goldfish Cracker (Culinary Mimic)
Cibus aurum (Commonly composed of Enriched Wheat Flour and Cheddar Cheese)
Anthropogenic Sedimentary-style Organic Solid
Carnelian
Chalcedony (cryptocrystalline quartz), SiO2 (Silicon Dioxide)
mineral
Mahogany Obsidian
Obsidian (volcanic glass with hematite/magnetite inclusions)
igneous
Diamond (set in Gold)
Diamond (pure carbon, C)
mineral
Jasper River Stone
Silicon Dioxide with Iron Oxide impurities (SiO2 + Fe2O3)
sedimentary
Green Chalcedony (likely Chrysoprase or dyed Green Agate)
Silicon Dioxide (SiO2) with nickel impurities or chromium/dye
mineral
Agate (Water-Worn Pebble)
Silicon Dioxide (SiO2) - Chalcedony
mineral
Quartzite
Quartzite (SiO2)
metamorphic
Jasper with Agate and Quartz Inclusions
Silicon Dioxide (SiO2) - Chalcedony / Quartz aggregate
sedimentary
Gold Ore
Gold-bearing Quartz (Native Gold, Au)
mineral
Gneiss (High-grade Metamorphic Rock)
Gneiss (Metamorphic silicate rock)
metamorphic
Amazonite
Amazonite (KAlSi3O8) - a variety of Microcline Feldspar
Mineral
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)
sedimentary
Amethyst
Amethyst (Silicon Dioxide, SiO2 + Fe)
mineral
Jasper with Quartz inclusions
Silicon Dioxide (SiO2) - Microcrystalline Chalcedony
sedimentary
Sunstone
Oligoclase (Plagioclase Feldspar subclass), (Ca,Na)(Al,Si)4O8
mineral
Copper Nugget
Native Copper (Cu)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite impurities
sedimentary
Agate Geode
Cryptocrystalline Quartz (SiO2)
mineral
Banded Iron Formation (BIF)
Banded Iron Formation (predominantly Hematite, Magnetite, and Chert/Quartz)
sedimentary
Chert (Honey Chert / Flint)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
sedimentary
Lepidolite on Pegmatite
Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)
mineral
Basalt
Extrusive mafic igneous rock
igneous
Limonite (Gozzany Iron)
Limonite (FeO(OH)·nH2O)
mineral
Sandstone (River Rock)
Arenite (composed primarily of SiO2)
sedimentary
Sandstone Cobble
Arenite (Secondary classification based on grain size)
sedimentary
Basalt
Basalt (Mafic igneous rock)
igneous
Basalt
Mafic volcanic rock (Basalt)
igneous
Basalt
Basalt (Mafic volcanic rock)
igneous
Gneiss
Gneiss (Metamorphic rock of variable composition, typically SiO2 rich)
metamorphic
Chert (Pink Chert / Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Garnet
Garnet Group (formula varies, e.g., Almasndine: Fe3Al2(SiO4)3)
mineral
Quartz Vein in Host Rock (clastic sediment)
Silicon Dioxide (SiO2) in matrix
sedimentary
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
sedimentary
Man-made Slag (Industrial Byproduct)
Anthropogenic Glassy Residue
not a natural rock
Quartzite
Quartzite (SiO2)
metamorphic