Rock Identifier

Category

Mineral (Biogenic Replacement)

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

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

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with Iron Oxide inclusions)

Petrified Wood (Silicified Wood (SiO2)) — sedimentary

Petrified Wood

Silicified Wood (SiO2)

Tiger's Eye (and Hematite/Jasper Matrix) (SiO2 (Pseudomorph of Quartz after Crocidolite) with Hematite/Magnetite) — mineral

Tiger's Eye (and Hematite/Jasper Matrix)

SiO2 (Pseudomorph of Quartz after Crocidolite) with Hematite/Magnetite

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxide inclusions)

Jasper with Quartz Vein (Silicon Dioxide (SiO2) - Microcrystalline Quartz) — sedimentary

Jasper with Quartz Vein

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Fossilized Sea Urchin (Echinoid) (Echinoidea (Class); commonly Clypeasteroida for sand dollar types) — sedimentary (fossil)

Fossilized Sea Urchin (Echinoid)

Echinoidea (Class); commonly Clypeasteroida for sand dollar types

sedimentary (fossil)

Jasper (Jasper (Silicate mineral, SiO2)) — sedimentary

Jasper

Jasper (Silicate mineral, SiO2)

Chert (Limestone-based) (Silicon dioxide (SiO2)) — sedimentary

Chert (Limestone-based)

Silicon dioxide (SiO2)

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)

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

Chert (Flint)

Chert (Silicon Dioxide, SiO2)

Galena (Lead Sulfide (PbS)) — mineral

Galena

Lead Sulfide (PbS)

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

Tiger's Eye

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

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

Celestite (Celestine)

Strontium sulfate (SrSO4)

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

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with iron oxides)

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

Petrified Wood

Silicified wood (SiO2 - Silicon Dioxide)

Blue Tiger's Eye (Silicon Dioxide (SiO2) with Crocidolite inclusions) — Mineral (Pseudomorph)

Blue Tiger's Eye

Silicon Dioxide (SiO2) with Crocidolite inclusions

Mineral (Pseudomorph)

Orthoceratid Fossil in Limestone (Orthoceras (extinct genus of Nautiloid Cephalopod)) — sedimentary

Orthoceratid Fossil in Limestone

Orthoceras (extinct genus of Nautiloid Cephalopod)

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

Chert (with Quartz Veining)

Microcrystalline Quartz (SiO2)

Red Jasper (Silicon Dioxide (SiO2) with Hematite impurities) — mineral

Red Jasper

Silicon Dioxide (SiO2) with Hematite impurities

Fossilized Brachiopod (Phylum Brachiopoda (General mineral composition: Calcite/CaCO₃ or Silica/SiO₂)) — sedimentary

Fossilized Brachiopod

Phylum Brachiopoda (General mineral composition: Calcite/CaCO₃ or Silica/SiO₂)

Chert (often called Flint in this context) (Microcrystalline or Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert (often called Flint in this context)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Tiger's Eye (Rough) (Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)) — Mineral

Tiger's Eye (Rough)

Pseudomorph of Quartz after Crocidolite (SiO2 with Iron inclusions)

Chalcedony (specifically Agate or Common Opal variety) (Cryptocrystalline Silica (SiO2)) — mineral

Chalcedony (specifically Agate or Common Opal variety)

Cryptocrystalline Silica (SiO2)

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

Chert (Nodule)

Silicon Dioxide (SiO2)

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

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Green Banded Chert (Agate/Jasper) (Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite) — sedimentary

Green Banded Chert (Agate/Jasper)

Silicon Dioxide (SiO2) with trace impurities of Chlorite or Glauconite

Chalcedony (specifically Agate or Water-worn Quartzite) (Silicon Dioxide (SiO2)) — mineral

Chalcedony (specifically Agate or Water-worn Quartzite)

Silicon Dioxide (SiO2)

Tiger's Eye (Rough Slab) (Pseudomorph of Quartz after Crocidolite (SiO2 with Fe-containing inclusions)) — mineral

Tiger's Eye (Rough Slab)

Pseudomorph of Quartz after Crocidolite (SiO2 with Fe-containing inclusions)

Flint (Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)) — Mineral

Flint

Chert (a form of cryptocrystalline quartz, chemical formula SiO₂)

Chert / Flint Nodules (Cryptocrystalline Quartz (SiO2)) — sedimentary

Chert / Flint Nodules

Cryptocrystalline Quartz (SiO2)

Chert (and Petrified Wood) (Silicon Dioxide (SiO2)) — sedimentary

Chert (and Petrified Wood)

Silicon Dioxide (SiO2)

Fossil Coral (Fossilized Scleractinia or Tabulata (various genera/species)) — Sedimentary

Fossil Coral

Fossilized Scleractinia or Tabulata (various genera/species)

Chert (specifically Jasper/Carnelian Agate) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (specifically Jasper/Carnelian Agate)

Microcrystalline Quartz (SiO2)

Tiger's Eye (Blue-Gold transition) (Pseudomorph of Quartz after Crocidolite (SiO2)) — metamorphic

Tiger's Eye (Blue-Gold transition)

Pseudomorph of Quartz after Crocidolite (SiO2)

Tiger's Eye (Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)) — metamorphic

Tiger's Eye

Pseudomorph of quartz after crocidolite (SiO2 with iron oxide inclusions)

Chert (Yellow Jasper/Flint) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Yellow Jasper/Flint)

Silicon Dioxide (SiO2)

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

Chert (Chert / Flint)

Silicon Dioxide (SiO2)

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

Red Jasper (Tumbled)

Silicon Dioxide (SiO2) with iron oxide inclusions

sedimentary/mineral

Fossilized Wood (Petrified Wood) (Silicified Wood (primarily quartz/chalcedony replacing organic matter)) — Sedimentary (with some aspects of mineral replacement)

Fossilized Wood (Petrified Wood)

Silicified Wood (primarily quartz/chalcedony replacing organic matter)

Sedimentary (with some aspects of mineral replacement)

Yellow Chert (Gold-colored River Pebble) (Microcrystalline Quartz (SiO2) with Limonite/Goethite staining) — sedimentary

Yellow Chert (Gold-colored River Pebble)

Microcrystalline Quartz (SiO2) with Limonite/Goethite staining

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

Petrified Wood

Silicified Wood (primarily SiO2)