Rock Identifier

Category

Mineral (Biogenic Replacement)

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

Tiffany Stone (Fluorite-bearing Opalized Breccia) — Rock/Mineralized Nodule

Tiffany Stone

Fluorite-bearing Opalized Breccia

Rock/Mineralized Nodule

Blue-green fluorite crystal (Fluorite (calcium fluoride, CaF₂)) — mineral

Blue-green fluorite crystal

Fluorite (calcium fluoride, CaF₂)

Fossilized Coral (Anthozoa (Fossilized)) — Sedimentary / Fossil

Fossilized Coral

Anthozoa (Fossilized)

Sedimentary / Fossil

Banded Jasper (Mookaite / Chert) (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Banded Jasper (Mookaite / Chert)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Shark Tooth (Chondrichthyes tooth) — fossil

Fossilized Shark Tooth

Chondrichthyes tooth

Red Jasper (Silicon Dioxide (SiO2) with Hematite inclusions) — sedimentary

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Chert (within Limestone) (Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) matrix) — sedimentary

Chert (within Limestone)

Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) matrix

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

Chert (Cherty Limestone / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Jasper (Jasper (Cryptocrystalline Quartz; SiO2)) — sedimentary

Jasper

Jasper (Cryptocrystalline Quartz; SiO2)

Fossil Coral (Hexagonaria or Rugose coral fossil (replaced by silica/chalcedony)) — fossil

Fossil Coral

Hexagonaria or Rugose coral fossil (replaced by silica/chalcedony)

Hematite / Jasper (Iron(III) oxide (Fe2O3) in Quartz (SiO2)) — mineral / sedimentary

Hematite / Jasper

Iron(III) oxide (Fe2O3) in Quartz (SiO2)

mineral / sedimentary

Petrified Bone (Fossil Bone) (Per mineralization fossil bone (varies by organism, predominantly replacement by SiO2 - Quartz/Chalcedony)) — fossil

Petrified Bone (Fossil Bone)

Per mineralization fossil bone (varies by organism, predominantly replacement by SiO2 - Quartz/Chalcedony)

Chalcopyrite (CuFeS2) — mineral

Chalcopyrite

CuFeS2

Polished ammonite fossil (Ammonoidea (likely a Jurassic or Cretaceous ammonite), preserved in limestone/mudstone) — fossil

Polished ammonite fossil

Ammonoidea (likely a Jurassic or Cretaceous ammonite), preserved in limestone/mudstone

Silver-bearing galena ore (Galena (PbS), likely in a quartz/carbonate-rich matrix with possible sulfide minerals) — mineral

Silver-bearing galena ore

Galena (PbS), likely in a quartz/carbonate-rich matrix with possible sulfide minerals

Carnelian (Red Chalcedony) (Silicon Dioxide (SiO2) with iron oxide impurities) — mineral

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

Sodalite (Sodium Aluminum Silicate Chloride (Na8Al6Si6O24Cl2)) — mineral

Sodalite

Sodium Aluminum Silicate Chloride (Na8Al6Si6O24Cl2)

Flint (Chert Node) (Silicon Dioxide (SiO2)) — sedimentary

Flint (Chert Node)

Silicon Dioxide (SiO2)

Fossilized Bone (Fossilized Vertebrate Bone (Per mineralized)) — fossil

Fossilized Bone

Fossilized Vertebrate Bone (Per mineralized)

Galena (likely) (Galena, lead sulfide (PbS)) — mineral

Galena (likely)

Galena, lead sulfide (PbS)

Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2)) — mineral

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Black Jasper (Etched) (Silicon Dioxide (SiO2) with impurities) — mineral

Black Jasper (Etched)

Silicon Dioxide (SiO2) with impurities

Chalcedony (Cryptocrystalline Quartz (SiO2)) — mineral

Chalcedony

Cryptocrystalline Quartz (SiO2)

Fossil Coral (Hexagonaria / Rugosa / Scleractinia) — fossil

Fossil Coral

Hexagonaria / Rugosa / Scleractinia

Chert Nodule (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Nodule

Microcrystalline Quartz (SiO2)

Fossilized Bone (Vertebrate Fossil Fragment (Calcium Phosphate / Hydroxyapatite)) — fossil

Fossilized Bone

Vertebrate Fossil Fragment (Calcium Phosphate / Hydroxyapatite)

Coprolite (Coprolite (fossilized feces)) — sedimentary

Coprolite

Coprolite (fossilized feces)

Dinosaur Fossil (Skull) (Dinosauria fossilis (Petrified Hydroxyapatite / Calcium Carbonate)) — sedimentary

Dinosaur Fossil (Skull)

Dinosauria fossilis (Petrified Hydroxyapatite / Calcium Carbonate)

Tumbled Stones Collection (Tiger's Eye, Snowflake Obsidian, Aventurine, etc.) (Silica minerals (primarily SiO2)) — mineral

Tumbled Stones Collection (Tiger's Eye, Snowflake Obsidian, Aventurine, etc.)

Silica minerals (primarily SiO2)

Magnetite (Lodestone) (Magnetite (Fe3O4)) — mineral

Magnetite (Lodestone)

Magnetite (Fe3O4)

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

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Magnetite (Magnetite (Iron(II,III) oxide, Fe3O4)) — mineral

Magnetite

Magnetite (Iron(II,III) oxide, Fe3O4)

Limonite-stained Chert (Microcrystalline Quartz (SiO2) with Goethite/Limonite (FeO(OH)·nH2O)) — sedimentary

Limonite-stained Chert

Microcrystalline Quartz (SiO2) with Goethite/Limonite (FeO(OH)·nH2O)

Tiger's Eye (Tiger's Eye (Pseudomorph of Quartz after Crocidolite), SiO2) — mineral

Tiger's Eye

Tiger's Eye (Pseudomorph of Quartz after Crocidolite), SiO2

Tiger's Eye (Unpolished) (Pseudomorph of Quartz after Crocidolite (SiO2)) — metamorphic

Tiger's Eye (Unpolished)

Pseudomorph of Quartz after Crocidolite (SiO2)

Petrified Wood (Silicified wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified wood (primarily SiO2)

Chalcedony (possibly agate or common quartz) (Microcrystalline quartz, SiO₂) — mineral

Chalcedony (possibly agate or common quartz)

Microcrystalline quartz, SiO₂

Tumbled Tiger's Eye (Silicon dioxide with crocidolite inclusions (SiO2)) — mineral

Tumbled Tiger's Eye

Silicon dioxide with crocidolite inclusions (SiO2)

Calcite (Calcite (CaCO₃)) — Mineral

Calcite

Calcite (CaCO₃)

Jasper or Agate (Chalcedony) (Silicon Dioxide (SiO2) with impurities) — sedimentary

Jasper or Agate (Chalcedony)

Silicon Dioxide (SiO2) with impurities

Petrified Wood (Silicified wood (Quartz replacement)) — fossil

Petrified Wood

Silicified wood (Quartz replacement)

Chert (with Patina) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (with Patina)

Microcrystalline Quartz (SiO2)