Ammolite
Biogenic gemstone (Aragonite, CaCO3)
mineral
Category
Organic Gemstone (Biogenic)
Browse organic gemstone (biogenic) specimens identified by the Rock Identifier community.
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Chert
Cryptocrystalline Quartz (SiO2)
sedimentary
Fossilized Shell Fragment / Mother of Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral
fossil
Fossiliferous Limestone
Biogenic Limestone (CaCO3)
sedimentary
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Oyster Shell Fragment
Crassostrea virginica (or related Bivalvia)
fossil
Coquina / Shelly Limestone
Coquina (Biogenic Limestone)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (CaCO3)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (CaCO3)
sedimentary
Human Skin (Epidermis/Dermis)
Integumentary tissue (High content of hydroxyapatite in bones, though the surface is biological)
Mineral-like biological tissue
Mother of Pearl (Nacre)
Aragonite (layered with organic polymers), CaCO3
mineral
Pearl
Calcium Carbonate (Aragonite) - CaCO3
mineral
Pearl
Calcium carbonate (CaCO3) - mainly Aragonite with Conchiolin
mineraloid
Fossiliferous Limestone
Biogenic Sedimentary Rock (CaCO3)
sedimentary
Pearl
Calcium carbonate (CaCO3) - Aragonite/Calcite variety
mineral
Fossilized Tiger Shark Tooth
Galeocerdo cuvier (fossilized hydroxylapatite)
sedimentary
Pearl
Aragonite (CaCO3) with Conchiolin
mineral
Fossiliferous Limestone
Fossiliferous Calcite (CaCO3)
sedimentary
Pearl
Biogenic CaCO3 (Aragonite)
mineral
Limestone with Fossil inclusions
Fossiliferous Limestone (CaCO3)
sedimentary
Mother of Pearl (Nacre)
Nacre (Aragonite/Conchiolin), CaCO3 + Organic Polymers
mineral
Chert (or Fossiliferous Limestone)
Microcrystalline Quartz (SiO2) / Calcium Carbonate (CaCO3)
sedimentary
Pearl (Biogenic Gemstone)
Calcium Carbonate (Aragonite and Calcite) with Conchiolin
gemstone
Fossiliferous Limestone
Fossiliferous Limestone (CaCO3)
sedimentary
Pearl
Calcium Carbonate (primarily Aragonite and Calcite), CaCO3
mineral
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Pearl (Cultured Freshwater)
Calcium Carbonate (Aragonite) - CaCO3
mineral
Pearl (Imitation or Cultured)
Calcium Carbonate (Aragonite/Calcite) - CaCO3
Mineraloid (Organic)
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Pearl (Biogenic Mineraloid)
Calcium carbonate (CaCO3) primarily as Aragonite
mineral
Fossiliferous Limestone
Limestone (CaCO3 - Calcium Carbonate)
sedimentary
Fossiliferous Limestone
Biogenic Sedimentary Rock (primarily CaCO3)
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with marine fossils
fossil
Pearl (as a biogenic mineral/gemstone)
Calcium Carbonate (mostly Aragonite), CaCO3
mineral
Fossiliferous Limestone (Shell Fragment)
Biogenic Limestone (Calcium Carbonate / CaCO3)
sedimentary
Fossiliferous Limestone
Calcite (CaCO3) matrix with biogenic fragments
sedimentary
Fossiliferous Limestone
Calcium Carbonate (CaCO3) with Bioclasts
sedimentary
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Mother of Pearl (Nacre) / Shell Fragment
Biogenic Calcium Carbonate (Aragonite and Conchiolin)
fossil
Chert (likely brown flint)
Microcrystalline quartz, SiO₂ (chalcedonic quartz aggregate)
sedimentary
Fossiliferous Limestone (Coquina / Shell Limestone)
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary