Pearl (in a decorative hair comb setting)
Calcium carbonate (CaCO3) primarily as Aragonite, bonded with Conchiolin
Organic Mineraloid
Category
Mineral (Biogenic Replacement)
Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.
Pyrite
Iron Sulfide (FeS2)
mineral
Nacre (Mother of Pearl)
Nacre (Biogenic Aragonite/Calcite composite, CaCO3)
mineral
Coprolite
Coprolite
sedimentary
Pearl
Biogenic Calcium Carbonate (Aragonite and Conchiolin), CaCO3
mineral
Tahitian Pearl
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Black Freshwater Pearls
Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3
mineral
Fossilized Bivalve Shell
Bivalvia (fossil specimen)
sedimentary
Pyrite (Iron Pyrites)
Iron Sulfide (FeS2)
mineral
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Calamites (Fossil)
Calamites sp. (Tracheophyta, Equisetopsida)
sedimentary
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Pyrite
Iron Sulfide (FeS2)
mineral
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Rhodonite
Rhodonite (Manganese Iron Magnesium Calcium Silicate - (Mn,Fe,Mg,Ca)SiO3)
mineral
Coquina
Biogenic Limestone (Calcite/Aragonite base, CaCO3)
sedimentary
Banded Flint (Chert)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Shark Teeth
Carcharhiniformes or Lamniformes species (common mineral: Fluorapatite/Ca5(PO4)3F)
sedimentary (fossilized organic matter)
Pyrite
Iron Sulfide (FeS2)
mineral
Tiger's Eye (with Blue Tiger's Eye / Hawk's Eye)
Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)
metamorphic
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral
Water and Silt (Sedimentary Environment)
Suspended Sediment / H2O (dihydrogen monoxide)
sedimentary
Chert (Chalcedony/Agate variety)
Silicon Dioxide (SiO2)
sedimentary
Chert (Flint) with Glauconite
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Sand Tiger Shark Tooth
Carcharias taurus / Striatolamia macrota (mineralized as Hydroxylapatite/Francolite)
sedimentary (fossil)
Tiger's Eye (Rough)
Pseudomorph of Quartz after Crocidolite (SiO2 with FeOOH inclusions)
metamorphic
Yellow Jasper
Tectosilicates (SiO2) with Goethite/Iron oxide inclusions
sedimentary
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Rainbow Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Ferruginous Sandstone (Gozzanous)
SiO2 (Quartz) with FeO(OH) (Goethite) or Fe2O3 (Hematite) coating
sedimentary
Queen Conch Shell (Biogenic Calcium Carbonate)
Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)
mineral
Fossil Coral
Cnidaria Anthozoa (Fossilized)
sedimentary
Tahitian Black Pearl
Biogenic Calcium Carbonate (Aragonite/Conchiolin Mixture), CaCO3
mineral
Chalcedony (Grey/White Agate)
Silicon Dioxide (SiO₂)
mineral
Sphalerite
Zinc Sulfide (Zn,Fe)S
mineral
Jasper
Silicon dioxide (SiO2)
sedimentary
Gastropod Fossil (Snail Internal Mold)
Gastropoda; internal mold (steinkern), often composed of Calcium Carbonate (CaCO3) or Silica (SiO2)
sedimentary
Brachiopod Fossil in Limestone
Phylum Brachiopoda (likely Order Spiriferida), CaCO3 (Calcite)
sedimentary
Fossilized Megalodon Tooth Fragment
Otodus megalodon (Carcharocles megalodon fossil)
sedimentary
Pyrite (Cube variety)
Iron Sulfide (FeS2)
mineral
Chalcedony (Agate)
Silicon Dioxide (SiO2)
mineral
Rhodonite
Manganese Silicate (Mn,Fe,Mg,Ca)SiO3
mineral