Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Category
Browse organic gemstone (not a rock or mineral in the traditional sense, but bio mineralized material) specimens identified by the Rock Identifier community.
Red Coral
Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.
Asphalt
Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)
Pearl (Biogenic Mineral)
Calcium Carbonate (primarily Aragonite) with Conchiolin; CaCO3
Mother of Pearl (Nacre)
Calcium Carbonate (primarily aragonite, with conchiolin)
Opalite (a synthetic glass)
Silicon Dioxide (SiO2) with various additives; not a true mineral but a man-made gem simulant
Pearl
Aragonite (CaCO3) with Conchiolin
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Amber
Amber (C10H16O)
Calligraphy Stone
Mariam Jasper (Fossiliferous Limestone with Hematite and Iron)
Spiny Oyster Shell
Spondylus (Calcium Carbonate, CaCO3)
Amber
Organic gemstone (Succinite)
Opalite (Man-made Glass)
Fused glass (typically made of dolomite and metal opacifiers)
Amber
Succinite
Shale
Laminated Mudstone
Pearl
Pearl (Calcium Carbonate with organic conchiolin, CaCO3)
Gneiss
Gneiss
Amber
Succinite (specifically for Baltic amber); Chemical formula approximately C10H16O
Amber
Succinite (fossilized resin)
Petrified Wood
Silicified wood (primarily SiO2)
Amber
Succinite
Opalite (a synthetic glass, often confused with Opal)
Silicon dioxide glass (SiO2nH2O, for natural opal)
Moss Agate
SiO2 (Silicon Dioxide) with dendritic inclusions
Blue Goldstone
Goldstone (artificial glass)
Turquoise
Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Amber
Succinite
Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite
Manganese Oxide Crust on Limestone
Manganese Oxides (e.g., Pyrolusite MnO2 or Romanechite) on CaCO3
Bauxite
Bauxite (Mixture including Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))
Amber
Succinite (a common variety of fossilized resin)
Fossiliferous Rock (likely Dinosaur Fossil in Matrix)
Permineralized Vertebrate Fossil (Calcium Carbonate/Silica replaced bone material)
Baltic Amber (Butterscotch or Egg Yolk Variety)
Succinite (chemical formula: C10H16O)
Tree Agate
Silicon Dioxide (SiO2) with Dendritic Inclusions
Pearls
Aragonite (calcium carbonate) and Conchiolin
Granite
Granite (Felsic Plutonic Rock)
Natural or Cultured Pearl
Calcium Carbonate (Aragonite and Conchiolin), CaCO3
Fossilized Shark Tooth in Matrix
Otodus sp. (likely Otodus obliquus)
Limonite (Iron-rich Siltstone / Sandstone base)
Hydrous ferric oxide mixture (FeO(OH)·nH2O)
Turquoise
Turquoise (CuAl6(PO4)4(OH)8·4H2O)
Turquoise and Spiny Oyster (Heishi style beads)
Turquoise (CuAl6(PO4)4(OH)8·4H2O) and Spondylus (Spiny Oyster shell)
Pearl
Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3
Banded Agate (Onyx type)
Silicon Dioxide (SiO2) - Cryptocrystalline Quartz
Quartz (Milky/Clear Variety)
Silicon Dioxide (SiO2)