Polished serpentine-rich stone (likely serpentinite)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with dark magnetite/mesh veins
metamorphic
Category
Sedimentary (With Some Aspects Of Mineral Replacement)
Browse sedimentary (with some aspects of mineral replacement) specimens identified by the Rock Identifier community.
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Chert (or Flint)
Chert (a cryptocrystalline variety of quartz, SiO2)
sedimentary
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Chert
Microcrystalline or cryptocrystalline quartz
sedimentary
Fossilized Nut / Coprolite / Concretion
Trace Fossil / Permineralized Plant Material
fossil
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossilized shark teeth in sedimentary matrix
Elasmobranchii teeth, chiefly shark; calcium-phosphate apatite (hydroxyapatite)
fossil
Magnetite (Iron Ore)
Magnetite (Fe3O4)
mineral
Chert (with potential fossil inclusion)
Microcrystalline Quartz (SiO2)
sedimentary
Weathered quartz-rich rock or fossil fragment
Indeterminate; likely quartz-bearing sandstone or siliceous fossil material
mineral
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Fossil / Permineralized Bone
Tyrannosaurus rex fossil (Hydroxylapatite replaced by various minerals)
sedimentary
Fossilized Gastropod Shell
Gastropoda (Class) replacement / internal cast (steinkern)
fossil
Weathered chert or siliceous limestone
Microcrystalline quartz (SiO₂), possibly with carbonate matrix
sedimentary
Pyrite (Fool's Gold) in Matrix
Iron Disulfide (FeS2)
mineral
Polished black stone, possibly black jasper or obsidian
Uncertain; candidates include microcrystalline quartz (SiO₂; black jasper) or volcanic glass (obsidian, SiO₂)
mineral
Jasper
Silicon dioxide (SiO2) with impurities
mineral
Galena
Lead(II) sulfide (PbS)
mineral
Metallic sulfide mineral specimen, possibly pyrite
Likely pyrite (FeS₂), though the photograph is insufficient for certainty
mineral
Possible flint or slag fragment
Microcrystalline quartz (chalcedony), or iron-rich industrial slag
mineral
Jasper
Silicon Dioxide (Microcrystalline Quartz, $SiO_2$)
sedimentary
Bivalve Fossil (Clam Fossil)
Class Bivalvia (likely Gryphaea or similar Order)
fossil
Fossil Bone Fragment
Petrified bone (permineralized hydroxyapatite)
fossil
Starfish Fossil
Asteroidea fossil
fossil
Coprolite
Coprolite
sedimentary
Polished brown jasper (likely brecciated or orbicular jasper)
Microcrystalline quartz/chalcedony, SiO₂, colored by iron oxides and other inclusions
mineral
Celestine (or Celestite)
Strontium sulfate (SrSO4)
mineral
Celestite (Celestine)
Strontium sulfate (SrSO4)
mineral
Fossil Coral
Anthozoa fossil (Calcite / SiO2 replacement)
fossil
Fossilized Brachiopod
Phylum Brachiopoda
fossil
Quartz (Jasper / Chert)
Silicon Dioxide (SiO2)
sedimentary
Magnetite
Magnetite (Fe3O4)
mineral
Fossil Shell
Brachiopod or Mollusk fossil
fossil
Chert (Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Tooth
Vertebrate Fossilized Tooth (Mineralized Biogenic Material)
fossil
Chert
Chert (Microcrystalline Quartz)
sedimentary
Gneiss
Gneiss (High-grade metamorphic rock)
metamorphic
Fossil brachiopod or bivalve shell fragment
Likely a fossilized, ribbed brachiopod; exact genus/species cannot be determined from the image
fossil
Sphalerite
Zinc Sulfide (Zn,Fe)S
mineral
Dendritic jasper (brecciated or orbicular jasper)
Microcrystalline quartz (SiO₂) with iron-oxide inclusions
mineral
Fossilized Dinosaur Bone
Perineralized Bone (Fluorapatite/Quartz replacement)
fossil
Chert (Jasper variety)
Silicon dioxide (SiO2)
sedimentary