Rock Identifier

Category

Mineral (Biogenic Replacement)

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

Agatized Dinosaur Bone (Permineralized Dinosaur Bone (Silicified/Agatized Bone)) — fossil

Agatized Dinosaur Bone

Permineralized Dinosaur Bone (Silicified/Agatized Bone)

Ammonite Fossil (Ammonoidea) — fossil

Ammonite Fossil

Ammonoidea

Chert Nodule (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Nodule

Microcrystalline Quartz (SiO2)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Chert (Green Chert or Jasper) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Green Chert or Jasper)

Silicon Dioxide (SiO2)

Chert (Jasper variety) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper variety)

Silicon Dioxide (SiO2)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

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

Galena

Galena (lead sulfide, PbS)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Jasper (Silicon Dioxide (SiO2)) — mineral

Jasper

Silicon Dioxide (SiO2)

Magnetite (or Magnetic Iron Ore) (Magnetite (Fe3O4)) — mineral

Magnetite (or Magnetic Iron Ore)

Magnetite (Fe3O4)

Blue Sphalerite (likely dyed or treated Druzy Quartz/Agate) (Zinc Sulfide (ZnS) or Silicon Dioxide (SiO2) with trade-name enhancement) — Mineral

Blue Sphalerite (likely dyed or treated Druzy Quartz/Agate)

Zinc Sulfide (ZnS) or Silicon Dioxide (SiO2) with trade-name enhancement

Tiger's Eye (Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)) — metamorphic

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)

Chert (Common Opal variant) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Common Opal variant)

Silicon Dioxide (SiO2)

Chert (Green Chert/Jasper) (Chert (primarily Microcrystalline Quartz, SiO2)) — sedimentary

Chert (Green Chert/Jasper)

Chert (primarily Microcrystalline Quartz, SiO2)

Chert (specifically Flint) (Microcrystalline or cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

Favosites Fossil (Honeycomb Coral) (Favosites (Extinct genus of Tabulate Coral)) — sedimentary

Favosites Fossil (Honeycomb Coral)

Favosites (Extinct genus of Tabulate Coral)

Flint / Chert with Cortex (Microcrystalline Quartz (SiO2)) — sedimentary

Flint / Chert with Cortex

Microcrystalline Quartz (SiO2)

Jasper (Banded Argillite/Chert mix) (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Jasper (Banded Argillite/Chert mix)

Silicon Dioxide (SiO2) with iron oxide inclusions

Fluorite (Rainbow Fluorite) (Calcium Fluoride (CaF2)) — mineral

Fluorite (Rainbow Fluorite)

Calcium Fluoride (CaF2)

Galena (Lead(II) sulfide (PbS)) — mineral

Galena

Lead(II) sulfide (PbS)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Fossilized bivalve or brachiopod shell (Indeterminate calcitic shell fossil; likely Bivalvia or Brachiopoda) — fossil

Fossilized bivalve or brachiopod shell

Indeterminate calcitic shell fossil; likely Bivalvia or Brachiopoda

Vuggy Chert / Silicified Limestone (Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions) — sedimentary

Vuggy Chert / Silicified Limestone

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Chert (often called Flint when dark or found in chalk) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint when dark or found in chalk)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Petrified Wood (Silicon Dioxide (SiO2) - Calcified / Silicified Wood) — sedimentary

Petrified Wood

Silicon Dioxide (SiO2) - Calcified / Silicified Wood

Banded Chert (Iron-stained) (Microcrystalline Quartz (SiO2) with Iron Oxides) — sedimentary

Banded Chert (Iron-stained)

Microcrystalline Quartz (SiO2) with Iron Oxides

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

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

Flint

SiO2 (Microcrystalline Quartz / Chert)

Fossilized Coral (Cnidaria fossil / Calcite-replaced coral) — fossil

Fossilized Coral

Cnidaria fossil / Calcite-replaced coral

Sea Shell (Fighting Conch Fragment) (Calcium Carbonate (CaCO3) - Strombus alatus fragment) — sedimentary (biogenic)

Sea Shell (Fighting Conch Fragment)

Calcium Carbonate (CaCO3) - Strombus alatus fragment

sedimentary (biogenic)

Fossil gastropod shell (Fossilized marine gastropod; exact genus/species requires locality and examination) — fossil

Fossil gastropod shell

Fossilized marine gastropod; exact genus/species requires locality and examination

Celestine (Celestite) (Strontium Sulfate (SrSO4)) — mineral

Celestine (Celestite)

Strontium Sulfate (SrSO4)

Flint (Silicon dioxide (SiO2)) — sedimentary

Flint

Silicon dioxide (SiO2)

Wollastonite (Calcium Inosilicate Mineral, CaSiO3) — mineral

Wollastonite

Calcium Inosilicate Mineral, CaSiO3

Fossilized Coral (Favosites) (Favosites goldfussi / Tabulata) — sedimentary

Fossilized Coral (Favosites)

Favosites goldfussi / Tabulata

Specular Hematite and Magnetite Ore (Iron Oxide (Fe2O3 and Fe3O4)) — mineral

Specular Hematite and Magnetite Ore

Iron Oxide (Fe2O3 and Fe3O4)

Yellow Jade (often Serpentine or Dolomite) (Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.) — Mineral, often a rock given its aggregate nature

Yellow Jade (often Serpentine or Dolomite)

Primarily Serpentine (Mg3Si2O5(OH)4) or Dolomite (CaMg(CO3)2), though the term 'yellow jade' is also sometimes applied to varieties of true nephrite or jadeite.

Mineral, often a rock given its aggregate nature

Tiger's Eye (SiO2 (Silicon Dioxide with inclusions of Goethite/Limonite)) — Metamorphic

Tiger's Eye

SiO2 (Silicon Dioxide with inclusions of Goethite/Limonite)

Chert (often called Jasper or Flint) (Microcrystalline Silica (SiO2)) — sedimentary

Chert (often called Jasper or Flint)

Microcrystalline Silica (SiO2)

Chert Arrowhead (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)