Rock Identifier

Category

Mineral (Biogenic Replacement)

Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.

Chert / Flint (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Pearl (Aragonite (CaCO3) with Conchiolin) — mineral

Pearl

Aragonite (CaCO3) with Conchiolin

Chert (Agate / Jasper pebble) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Agate / Jasper pebble)

Microcrystalline Quartz (SiO2)

Spondylus Oyster Calcification / Fossilized Oyster (Spondylus (Thorny Oyster) / Calcium Carbonate (CaCO3)) — sedimentary

Spondylus Oyster Calcification / Fossilized Oyster

Spondylus (Thorny Oyster) / Calcium Carbonate (CaCO3)

Possible fossilized bone fragment (Indeterminate mineralized bone; taxon and age cannot be determined from the photo) — fossil

Possible fossilized bone fragment

Indeterminate mineralized bone; taxon and age cannot be determined from the photo

Pearl (Calcium Carbonate (primarily Aragonite and Calcite), CaCO3) — mineral

Pearl

Calcium Carbonate (primarily Aragonite and Calcite), CaCO3

Pearl (Aragonite / Calcium Carbonate (CaCO3)) — mineral

Pearl

Aragonite / Calcium Carbonate (CaCO3)

Pearl (Aragonite and Calcite (CaCO3) with Conchiolin) — mineral

Pearl

Aragonite and Calcite (CaCO3) with Conchiolin

Pearl (Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3) — mineral

Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Calcite (Calcium Carbonate (CaCO3)) — mineral

Calcite

Calcium Carbonate (CaCO3)

Flint or chert fragment (Microcrystalline quartz (SiO₂), commonly chalcedony with possible iron-oxide impurities) — sedimentary

Flint or chert fragment

Microcrystalline quartz (SiO₂), commonly chalcedony with possible iron-oxide impurities

Fossiliferous Limestone containing a Brachiopod or Mollusk Impression (Biogenic Sedimentary Rock / Fossiliferous Limestone) — sedimentary

Fossiliferous Limestone containing a Brachiopod or Mollusk Impression

Biogenic Sedimentary Rock / Fossiliferous Limestone

Oyster Shell (Biogenic Calcium Carbonate) (Crassostrea virginica (or related species) - Calcium Carbonate (CaCO3)) — sedimentary

Oyster Shell (Biogenic Calcium Carbonate)

Crassostrea virginica (or related species) - Calcium Carbonate (CaCO3)

Nacre (Mother of Pearl) (Nacre (Biogenic Aragonite/Calcite composite, CaCO3)) — mineral

Nacre (Mother of Pearl)

Nacre (Biogenic Aragonite/Calcite composite, CaCO3)

Black Pearl (Tahitian-style Cultured Pearl) (Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)) — mineral

Black Pearl (Tahitian-style Cultured Pearl)

Calcium Carbonate (Aragonite) with Conchiolin (CaCO3)

Possible fossilized shell or coral fragment (Indeterminate biogenic carbonate, likely calcite (CaCO₃)) — fossil

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Fossilized Shell Fragment / Mother of Pearl (Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral) — fossil

Fossilized Shell Fragment / Mother of Pearl

Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral

Chert (Flint) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Flint)

Microcrystalline Quartz (SiO2)

Mother of Pearl (Nacre) (Nacre (Aragonite/Conchiolin), CaCO3 + Organic Polymers) — mineral

Mother of Pearl (Nacre)

Nacre (Aragonite/Conchiolin), CaCO3 + Organic Polymers

Pyrite in Quartz (FeS2 (Iron Pyrite) with SiO2 (Quartz)) — Mineral/Igneous/Hydrothermal

Pyrite in Quartz

FeS2 (Iron Pyrite) with SiO2 (Quartz)

Mineral/Igneous/Hydrothermal

Oyster Shell (Aragonite/Calcite) (Calcium Carbonate (CaCO3)) — sedimentary

Oyster Shell (Aragonite/Calcite)

Calcium Carbonate (CaCO3)

Banded Chert / Agate (Silicon Dioxide (SiO2)) — sedimentary

Banded Chert / Agate

Silicon Dioxide (SiO2)

Beaded mineral/crystal jewelry (likely turquoise and coral accents) (Variable; blue beads may be turquoise (CuAl6(PO4)4(OH)8·4H2O), with possible dyed howlite, glass, or composite materials) — gemstone

Beaded mineral/crystal jewelry (likely turquoise and coral accents)

Variable; blue beads may be turquoise (CuAl6(PO4)4(OH)8·4H2O), with possible dyed howlite, glass, or composite materials

Chalcedony (Botryoidal) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (Botryoidal)

Silicon Dioxide (SiO2)

Polished fossil-bearing limestone pebble (Bioclastic limestone, chiefly calcite (CaCO₃), possibly containing a small shell or coral fragment) — sedimentary

Polished fossil-bearing limestone pebble

Bioclastic limestone, chiefly calcite (CaCO₃), possibly containing a small shell or coral fragment

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Tumbled jasper (Microcrystalline quartz (chalcedony), chiefly SiO₂, colored by iron oxides and other impurities) — mineral

Tumbled jasper

Microcrystalline quartz (chalcedony), chiefly SiO₂, colored by iron oxides and other impurities

Ammolite (Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)) — mineral

Ammolite

Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)

Pearl (Biogenic Calcium Carbonate (Aragonite and Conchiolin), CaCO3) — mineral

Pearl

Biogenic Calcium Carbonate (Aragonite and Conchiolin), CaCO3

Tahitian Pearl (Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3) — mineral

Tahitian Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Black Freshwater Pearls (Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3) — mineral

Black Freshwater Pearls

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

Atlantic Calico Scallop (Biogenic Aragonite/Calcite) (Argopecten gibbus (Chemical: CaCO3)) — mineral

Atlantic Calico Scallop (Biogenic Aragonite/Calcite)

Argopecten gibbus (Chemical: CaCO3)

Pyrite (Fool's Gold) (Iron Disulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Pearl (Calcium Carbonate (Aragonite) - CaCO3) — mineral

Pearl

Calcium Carbonate (Aragonite) - CaCO3

Chert (varieties include Flint and Jasper) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Pyrite (Iron Disulfide (FeS2)) — mineral

Pyrite

Iron Disulfide (FeS2)

Fossil Coral (Scleractinia (Fossilized Hexacoral)) — fossil

Fossil Coral

Scleractinia (Fossilized Hexacoral)

Polished brecciated jasper (likely picture jasper) (Silica-rich microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and clay inclusions) — metamorphic

Polished brecciated jasper (likely picture jasper)

Silica-rich microcrystalline quartz/chalcedony, SiO₂, with iron-oxide and clay inclusions

Fossilized Shark Tooth (Otodus) (Otodus sp. (calcium phosphate/hydroxylellite)) — sedimentary

Fossilized Shark Tooth (Otodus)

Otodus sp. (calcium phosphate/hydroxylellite)

Calamites (Calamites (Pith cast fossil)) — sedimentary

Calamites

Calamites (Pith cast fossil)

Pearl (Aragonite (CaCO3) with Conchiolin) — mineral

Pearl

Aragonite (CaCO3) with Conchiolin

Pyrite (Iron Disulfide (FeS2)) — mineral

Pyrite

Iron Disulfide (FeS2)