Rock Identifier

Category

Mineral (Biogenic Replacement)

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

Iron-rich concretion or weathered ironstone (Limonite/goethite-rich iron oxide (hydrated FeO(OH)·nH₂O), possibly with hematite) — mineral

Iron-rich concretion or weathered ironstone

Limonite/goethite-rich iron oxide (hydrated FeO(OH)·nH₂O), possibly with hematite

Agated Chert (Microcrystalline Quartz (SiO2)) — sedimentary

Agated Chert

Microcrystalline Quartz (SiO2)

Fossilized bone, likely a large vertebrate limb or rib fragment (Petrified bone; exact taxon indeterminate from the image) — fossil

Fossilized bone, likely a large vertebrate limb or rib fragment

Petrified bone; exact taxon indeterminate from the image

Coprolite (Fossilized Feces) — fossil

Coprolite

Fossilized Feces

Fossilized Ray Barb (Stinger) Fragment (Myliobatiformes indet. (Fossil stingray spine)) — fossil

Fossilized Ray Barb (Stinger) Fragment

Myliobatiformes indet. (Fossil stingray spine)

Polished red-and-black jasper (Jasper, microcrystalline quartz (SiO₂), colored by iron oxides and other inclusions) — mineral

Polished red-and-black jasper

Jasper, microcrystalline quartz (SiO₂), colored by iron oxides and other inclusions

Tumbled red jasper (likely brecciated jasper) (Jasper, microcrystalline quartz (SiO₂) with iron-oxide inclusions) — mineral

Tumbled red jasper (likely brecciated jasper)

Jasper, microcrystalline quartz (SiO₂) with iron-oxide inclusions

Galena-bearing ore (tentative) (Galena, lead sulfide (PbS), possibly mixed with quartz or sulfide minerals) — mineral

Galena-bearing ore (tentative)

Galena, lead sulfide (PbS), possibly mixed with quartz or sulfide minerals

Galena (Galena (lead sulfide, PbS), possibly a galena-rich ore specimen) — mineral

Galena

Galena (lead sulfide, PbS), possibly a galena-rich ore specimen

Likely galena-bearing ore (Galena (PbS), possibly with sphalerite or other sulfides) — mineral

Likely galena-bearing ore

Galena (PbS), possibly with sphalerite or other sulfides

Galena-bearing sulfide specimen (Galena (PbS), possibly with sphalerite and iron sulfides) — mineral

Galena-bearing sulfide specimen

Galena (PbS), possibly with sphalerite and iron sulfides

Likely galena-bearing ore (Galena (PbS), possibly mixed with quartz and sulfide minerals) — mineral

Likely galena-bearing ore

Galena (PbS), possibly mixed with quartz and sulfide minerals

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

Galena

Galena (lead sulfide, PbS)

Likely galena-bearing ore (Galena (lead sulfide, PbS), possibly mixed with sulfide minerals) — mineral

Likely galena-bearing ore

Galena (lead sulfide, PbS), possibly mixed with sulfide minerals

Jasper Agate (Silicon dioxide (SiO2)) — mineral

Jasper Agate

Silicon dioxide (SiO2)

Chalcedony (Common Opal variant) (Silicon dioxide (SiO2) with varying levels of hydration) — mineral

Chalcedony (Common Opal variant)

Silicon dioxide (SiO2) with varying levels of hydration

Polished ammonite fossil (Ammonoidea; commonly Jurassic or Cretaceous ammonite, often preserved in calcite or aragonite) — fossil

Polished ammonite fossil

Ammonoidea; commonly Jurassic or Cretaceous ammonite, often preserved in calcite or aragonite

Fossilized bivalve shell fragment (Calcitic mollusk shell, commonly Bivalvia; exact genus cannot be determined from the image) — fossil

Fossilized bivalve shell fragment

Calcitic mollusk shell, commonly Bivalvia; exact genus cannot be determined from the image

Fossilized marine shell fragment (Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)) — fossil

Fossilized marine shell fragment

Likely a bivalve or gastropod shell preserved as calcite (CaCO₃)

Fossilized bivalve shell fragment (Bivalvia; commonly aragonite or calcite (CaCO₃), often recrystallized during fossilization) — fossil

Fossilized bivalve shell fragment

Bivalvia; commonly aragonite or calcite (CaCO₃), often recrystallized during fossilization

Fossil trilobite, likely enrolled specimen (Trilobita; exact genus/species cannot be determined from the image) — fossil

Fossil trilobite, likely enrolled specimen

Trilobita; exact genus/species cannot be determined from the image

Fossilized trilobite (Trilobita; likely an enrolled asaphid or phacopid trilobite) — fossil

Fossilized trilobite

Trilobita; likely an enrolled asaphid or phacopid trilobite

Chert with Jasper/Quartz Inclusions (Silicon Dioxide (SiO2)) — sedimentary

Chert with Jasper/Quartz Inclusions

Silicon Dioxide (SiO2)

Fossil coral (likely solitary rugose coral) (Rugosa; possibly genus Heliophyllum or similar) — fossil

Fossil coral (likely solitary rugose coral)

Rugosa; possibly genus Heliophyllum or similar

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

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Nodule) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Nodule)

Silicon Dioxide (SiO2)

Chert (variously known as Flint or Microcrystalline Quartz) (Silicon dioxide (SiO2)) — sedimentary

Chert (variously known as Flint or Microcrystalline Quartz)

Silicon dioxide (SiO2)

Tiger's Eye (Pseudomorph of quartz after crocidolite (SiO2)) — metamorphic

Tiger's Eye

Pseudomorph of quartz after crocidolite (SiO2)

Fluorite (Calcium fluoride (CaF2)) — mineral

Fluorite

Calcium fluoride (CaF2)

Jasper (Microcrystalline Quartz (SiO2)) — gemstone

Jasper

Microcrystalline Quartz (SiO2)

Bivalve Fossil (Internal Mold/Steinkern) (Class Bivalvia (Fossilized Mold)) — sedimentary

Bivalve Fossil (Internal Mold/Steinkern)

Class Bivalvia (Fossilized Mold)

Fossil gastropod shell (Fossilized or mineral-replaced gastropod (class Gastropoda), exact genus indeterminate) — fossil

Fossil gastropod shell

Fossilized or mineral-replaced gastropod (class Gastropoda), exact genus indeterminate

Fossilized Echinoid Fragment (Calycinal/Boss Fossil) (Echinodermata fossil fragment) — fossil

Fossilized Echinoid Fragment (Calycinal/Boss Fossil)

Echinodermata fossil fragment

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Jasper (Silicon dioxide (SiO2)) — sedimentary

Jasper

Silicon dioxide (SiO2)

Polished orbicular jasper (likely ocean jasper) (Silicified microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions) — gemstone

Polished orbicular jasper (likely ocean jasper)

Silicified microcrystalline quartz/chalcedony (SiO₂), with iron-oxide and other mineral inclusions

Shell fossil or shell fragment (Likely a bivalve shell, composed mainly of calcium carbonate (aragonite/calcite); exact species cannot be determined from one photo) — fossil

Shell fossil or shell fragment

Likely a bivalve shell, composed mainly of calcium carbonate (aragonite/calcite); exact species cannot be determined from one photo

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

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

Green Jasper / Chert

Microcrystalline Quartz (SiO2)

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)

Chert Nodule (Chert (Microcrystalline Silicon Dioxide, SiO2)) — sedimentary

Chert Nodule

Chert (Microcrystalline Silicon Dioxide, SiO2)

Flint (SiO2 (Cryptocrystalline Quartz)) — sedimentary

Flint

SiO2 (Cryptocrystalline Quartz)