Rock Identifier

Category

Mineral (Biogenic Replacement)

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

Chert Geode or Nodule (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Geode or Nodule

Microcrystalline Quartz (SiO2)

sedimentary
Fossil Shell (Bivalve) (Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3) — sedimentary

Fossil Shell (Bivalve)

Class Bivalvia (Likely a member of the Ostreidae or Gryphaeidae family), CaCO3

sedimentary
Hematite (Botryoidal/Kidney Ore) (Iron(III) oxide (Fe2O3)) — mineral

Hematite (Botryoidal/Kidney Ore)

Iron(III) oxide (Fe2O3)

mineral
Chalcedony Nodule (Commonly known as Agate or Chert) (Microcrystalline Quartz (SiO2)) — mineral

Chalcedony Nodule (Commonly known as Agate or Chert)

Microcrystalline Quartz (SiO2)

mineral
Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur). (Galena (PbS)) — mineral

Note: Image shows a biological specimen (Rat), not a rock. Representative geological equivalent: Galena (due to lead-grey colors in fur).

Galena (PbS)

mineral
Fossilized Bone Fragment (Permineralized Skeletal Element (Likely Vertebrate)) — sedimentary

Fossilized Bone Fragment

Permineralized Skeletal Element (Likely Vertebrate)

sedimentary
Yellow Jasper (Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2) — sedimentary

Yellow Jasper

Jasper (Silicon Dioxide with Iron Oxide inclusions), SiO2

sedimentary
Chert Nodule in Limestone (Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)) — sedimentary

Chert Nodule in Limestone

Chert (Microcrystalline Quartz, SiO2) and Limestone (Calcium Carbonate, CaCO3)

sedimentary
Pyrite (on Quartz/Host Rock) (Iron Sulfide (FeS₂)) — mineral

Pyrite (on Quartz/Host Rock)

Iron Sulfide (FeS₂)

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

Galena

Lead(II) sulfide (PbS)

mineral
N/A - Image is non-geological (Acrylonitrile Butadiene Styrene (ABS) or Polypropylene (PP)) — Synthetic material (Plastic/Polymer)

N/A - Image is non-geological

Acrylonitrile Butadiene Styrene (ABS) or Polypropylene (PP)

Synthetic material (Plastic/Polymer)
Barite (Barium Sulfate (BaSO4)) — mineral

Barite

Barium Sulfate (BaSO4)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

metamorphic
Red Jasper (Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)) — sedimentary

Red Jasper

Jasper (Silicon Dioxide, SiO2 with iron oxide impurities)

sedimentary
Petoskey Stone (Hexagonaria percarinata (Fossilized Rugose Coral)) — sedimentary

Petoskey Stone

Hexagonaria percarinata (Fossilized Rugose Coral)

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

Chert (Cherty Limestone / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

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

Jasper

Jasper (Cryptocrystalline Quartz; SiO2)

sedimentary
Red Jasper (Silicon Dioxide (SiO2) with iron oxide inclusions) — sedimentary

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

sedimentary
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)

metamorphic
Chert Pebble with Quartz Veins (Microcrystalline Quartz (SiO2)) — sedimentary

Chert Pebble with Quartz Veins

Microcrystalline Quartz (SiO2)

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

Sodalite

Sodium Aluminum Silicate Chloride (Na8Al6Si6O24Cl2)

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

Carnelian (Red Chalcedony)

Silicon Dioxide (SiO2) with iron oxide impurities

mineral
Lapis Lazuli (Tumbled) (Lazurite-dominated contact metamorphic rock) — metamorphic

Lapis Lazuli (Tumbled)

Lazurite-dominated contact metamorphic rock

metamorphic
Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

mineral
Rhodonite (Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3) — mineral

Rhodonite

Manganese Inosilicate (Mn,Fe,Mg,Ca)SiO3

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

Fossilized Coral

Anthozoa (Fossilized)

Sedimentary / Fossil
Chert (Jasper variety) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Jasper variety)

Microcrystalline Quartz (SiO2)

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

Magnetite

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

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

Tiger's Eye (Unpolished)

Pseudomorph of Quartz after Crocidolite (SiO2)

metamorphic
Ammonite Fossil (Ammonoidea (subclass)) — sedimentary

Ammonite Fossil

Ammonoidea (subclass)

sedimentary
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

sedimentary
Petrified Wood (Silicified wood (primarily SiO2 - Silicon Dioxide)) — mineral

Petrified Wood

Silicified wood (primarily SiO2 - Silicon Dioxide)

mineral
Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

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

Chert (Common Opal variant)

Silicon Dioxide (SiO2)

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

Chert (specifically Flint)

Microcrystalline or cryptocrystalline Quartz (SiO2)

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

Dinosaur Fossil (Skull)

Dinosauria fossilis (Petrified Hydroxyapatite / Calcium Carbonate)

sedimentary
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

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

Petrified Wood

Silicon Dioxide (SiO2) - Calcified / Silicified Wood

sedimentary
Chalcedony (Cryptocrystalline Quartz (SiO2)) — mineral

Chalcedony

Cryptocrystalline Quartz (SiO2)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

metamorphic
Calcite (likely a tumbled specimen) (Calcite (CaCO 3 )) — Mineral

Calcite (likely a tumbled specimen)

Calcite (CaCO 3 )

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

Tiger's Eye

SiO2 (Silicon Dioxide with inclusions of Goethite/Limonite)

Metamorphic