White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
mineral
Category
Man Made Object (Coin)
Browse man made object (coin) specimens identified by the Rock Identifier community.
Fluorite
Calcium Fluoride (CaF2)
mineral
Anthracite Coal
Anthracite (Carbon-rich metamorphic coal)
metamorphic
Jasper (Banded Jasper)
Silicon Dioxide (SiO2) with impurities
sedimentary
Snowflake Obsidian (or similar porphyritic volcanic rock)
Obsidian with Spherulites (if glassy), or Porphyritic Rhyolite/Andesite (if crystalline groundmass)
igneous
Red Jasper
Argillaceous microcrystalline quartz (SiO2 with Fe2O3 inclusions)
sedimentary
Yellow Jasper
Silicon Dioxide (SiO2) with iron inclusions
sedimentary
Smoky Quartz (with possible Feldspar inclusions)
Silicon Dioxide (SiO2)
mineral
Green Aventurine
Aventurine (a variety of Quartz, SiO2)
mineral
Blue Chalcedony
Chalcedony (Silicon Dioxide, SiO2)
mineral
Banded Jasper
Silicon Dioxide (SiO2)
Mineral/Sedimentary Rock (as a cryptocrystalline variety of quartz)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Chert (Nodular or Massive Variety)
Cryptocrystalline Quartz (SiO2)
sedimentary
Angel Aura Quartz (Treated Clear Quartz)
Silicon Dioxide (SiO2) coated with Vaporized Silver and Platinum
mineral
Chert (Grey-Green Flint)
Microcrystalline silicon dioxide (SiO2)
sedimentary
Chert (variations include Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Specular Hematite (Specularite)
Iron Oxide (Fe2O3)
mineral
Rutilated Quartz (likely Citrine or Smoky Quartz with Rutile inclusions)
SiO2 with TiO2 inclusions (Quartz with Rutile)
Mineral
Chrysoprase
Chrysoprase (a variety of Chalcedony, SiO₂)
Mineral
Granodiorite with Quartz Veining
Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins
igneous
Smurf Rock (Fictional Interpretation)
Cyanus Anthropomorphicus (Geologic Simulation)
Artificial/Fantasy Object
Silver Sheen Obsidian
Volcanic Glass (Amorphous Silicon Dioxide - SiO2 with impurities)
igneous
Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide, SiO2)
mineral
Green Slag Glass
Amorphous Silica / Glassy Blast Furnace Slag
Mineraloid (Industrial byproduct)
Malachite
Malachite (Cu2(CO3)(OH)2 - a copper carbonate hydroxide mineral)
Mineral
Moonstone
Orthoclase Feldspar (formula: (K,Na)AlSi3O8)
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Obsidian
Volcanic Glass (Amorphous SiO2)
igneous
Diamond (as set in a metal alloy ring)
Diamond (Pure Carbon, C)
mineral
Chert (often called Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Grey Granite
Phaneritic Felsic Intrusive Igneous Rock
igneous
Sandstone (Red/Brown Variety)
Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)
sedimentary
Pearl (Biogenic)
Nacre / Calcium Carbonate (CaCO3)
mineral
Sunstone
Aventurine Feldspar (Plagioclase Feldspar with inclusions)
mineral
Diamond
Carbon (C)
mineral
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Chert (Iron-stained)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Chalk
CaCO3 (primarily Calcium Carbonate), biogenic sedimentary rock
Sedimentary
Granite
Phaneritic Igneous Rock (composed mostly of Quartz, Alkali Feldspar, and Plagioclase)
igneous
Granite
Phaneritic plutonic rock (SiO2 typically >69%)
igneous