Red cabochon gemstone, likely carnelian
Carnelian: orange-red chalcedony, microcrystalline quartz (SiO₂)
gemstone
Category
Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material)
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Learn about Organic Gemstone (Not A Rock Or Mineral In The Traditional Sense, But Bio Mineralized Material) in the encyclopedia
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Fossilized Shell
Invertebrate fossil (Bivalvia or Brachiopoda)
fossil
Sedimentary Rock (Limestone or Siltstone pebble)
Sedimentary rock fragment
sedimentary
Iron-rich concretion or weathered ironstone
Goethite–hematite limonite aggregate; commonly described as limonite or ironstone
sedimentary
Sandstone
Arenite
sedimentary
Seashell Fossil
Gastropoda fossil
fossil
Fossilized Nut / Coprolite / Concretion
Trace Fossil / Permineralized Plant Material
fossil
Red Sandstone
Sandstone (Quartz Arenite / Arkose with Hematite cement)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Emerald
Beryl (Be3Al2(SiO3)6)
gemstone
Fossilized Shark Tooth
Chondrichthyes (Class) fossilized tooth
fossil
Pink Quartz
Silicon Dioxide (SiO2)
mineral
Rose Quartz
Silicon Dioxide (Quartz), SiO2
mineral
Sedimentary Rock with Crafts (Pet Rock)
Sedimentary rock decorated with synthetic materials
sedimentary
Sodalite
Na8(Al6Si6O24)Cl2
mineral
Limestone or Sandstone Cobble
Sedimentary rock (Calcium carbonate or Quartz based)
sedimentary
Garnet (likely Almandine or Pyrope)
Garnet Group (e.g., Almandine: Fe3Al2(SiO4)3; Pyrope: Mg3Al2(SiO4)3)
Mineral
Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Starfish Fossil
Asteroidea fossil
fossil
Amber
Succinite (approximate formula C10H16O)
mineral
Red Coral
Corallium rubrum (Calcium Carbonate, CaCO3)
Organic Gemstone (Sedimentary classification)
Concrete or asphalt-like aggregate surface with a dark fragment
Uncertain; likely artificial concrete containing mixed lithic aggregate, not a natural rock
sedimentary
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Yellow Jasper
Silicon Dioxide (SiO2) - variety of Chalcedony
sedimentary
Sandstone
Arenite
sedimentary
Fossilized Shark Tooth
Chondrichthyes (Class)
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Amber (Copal)
Organic gemstone, fossilized tree resin (often immature amber or copal)
Mineral
Ruby
Corundum (Al2O3:Cr)
mineral
Pearl and Garnet Glass
Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass
mineral and glass
Petrified Wood
Silicified Wood (SiO2)
fossil
Amber
Succinite (Resinite), C10-H16-O
mineral
Fossilized Bone
Permineralized Bone (Vertebrate Fossil)
fossil
Fossil Shark Tooth
Selachii (fossilized dentition)
fossil
Petrified Wood
Silicified wood / Permineralized wood (SiO2)
fossil
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Chert (concretionary/nodular variant)
Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions
sedimentary
Weathered vuggy quartz-rich rock (probable silicified limestone or quartz breccia)
Microcrystalline quartz (SiO₂) with calcite (CaCO₃), iron oxides, and minor clay minerals
sedimentary