Petrified Wood
Silicified wood (Quartz replacement, SiO2)
fossil
Category
Mineral (Biogenic Replacement)
Browse mineral (biogenic replacement) specimens identified by the Rock Identifier community.
Hematite (Iron Ore)
Hematite (Fe2O3)
mineral
Fossilized Bone (Petrified Bone)
Permineralized Vertebrate Remains
sedimentary
Raw galena specimen
Galena (lead sulfide, PbS)
mineral
Quartz (likely Chalcedony or Chert)
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood / Fossilized Wood (SiO2)
sedimentary
Petrified wood
Silicified fossil wood; commonly quartz (SiO₂) replacing wood
fossil
Chert (Common Opal/Agatized Rock)
Microcrystalline Quartz (SiO2) with potential Chalcedony/Opaline silica
sedimentary
Fossilized bivalve shell in limestone
Calcitic fossil shell; likely an oyster or other rudist/bivalve (Bivalvia), preserved in carbonate rock
fossil
Fossil Belemnite Guard
Belemnitella spp. (rostrum)
fossil
Jasper (Brown Iron-Rich Variety)
Silicon Dioxide (SiO2) with Fe2O3 (Iron Oxide/Crystalline Quartz)
sedimentary
Banded Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Goniatite Fossil
Order Goniatitida
fossil
Chert (Jasper/Agate variety)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Jasper/Limonitic Chert)
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Chert with Brachiopod Impression
Chert (SiO2) containing Brachiopoda fossil remains
sedimentary
Metallic sulfide ore, likely galena-bearing rock
Galena (lead sulfide, PbS), possibly with pyrite or other sulfides
mineral
Amethyst
Silicon Dioxide (SiO2) with trace Iron (Fe3+)
mineral
Chert (Flint)
Silicon Dioxide (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Thulite in Matrix
Pink Zoisite - Ca2Al3(SiO4)3(OH)
metamorphic
Fossil Coral
Rugosa or Tabulata coral fossil
fossil
Chert (specifically Flint or Jasperoid)
Silicon Dioxide (SiO2)
sedimentary
Fossilized Echinoid (Sea Urchin)
Echinoidea (Fossil)
sedimentary
Bismuth
Bismuth (Bi)
mineral
Petrified Wood
Silicified wood (Quartz / Chalcedony replacement)
fossil
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Chert (specifically Flint or Jasper variant)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Commonly known as Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Hematite
Iron(III) oxide (Fe2O3)
mineral
Likely metallic mineral specimen
Probably galena (lead sulfide, PbS), though visual identification is uncertain
mineral
Likely polished dark pebble
Indeterminate; possibly basalt, black jasper, or a dark sulfide-rich stone
mineral
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2 with iron inclusions)
mineral
Sphalerite in Matrix (Polished Point)
Zinc sulfide (Zn,Fe)S
mineral
Chert with Chalcedony/Quartz Vug
Cryptocrystalline Silica (SiO2)
sedimentary
Synthetic Sapphire and Ion-X Glass
Single-crystal Alumina (Al2O3) and Ion-strengthened Aluminosilicate Glass
mineral
Fossilized Shark Teeth
Otodus sp. (Eocene Sand Tiger/Mackerel Shark)
fossil
Yellow Chert or Jasper
Silicon Dioxide (SiO2)
sedimentary
Galena
Lead(II) sulfide (PbS)
mineral
Fossilized Coral (Petrified Coral)
Lithostrotionella (example genus) / Scleractinia
fossil
Tumbled brown stone, likely tiger’s-eye or jasper
Quartz-rich microcrystalline silica, likely SiO₂ (possible tiger’s-eye; identification uncertain from image)
mineral
Galena
Lead(II) sulfide (PbS)
mineral