Weathered shale or mudstone
Clastic mudrock, chiefly clay minerals, quartz, and feldspar
Category
Browse organic (geological interest) specimens identified by the Rock Identifier community.
Weathered shale or mudstone
Clastic mudrock, chiefly clay minerals, quartz, and feldspar
Chalk
Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (composed primarily of Quartz sand with Hematite/Goethite shell)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert / River Jasper
Microcrystalline Quartz (SiO2)
Petrified Wood
Petrified Wood (Silicified Wood)
Petrified Wood
Silicified Wood (SiO2)
Fossil Coral
Phylum Cnidaria / Rugosa or Tabulata
Limestone (Concretionary or Tufa)
Calcium Carbonate (CaCO3)
Petrified Wood
Silicified Wood (SiO2)
Chert (with Quartz Veining)
Chert (formula: SiO2)
Petrified Wood
Silicified Wood (SiO2)
Moss Agate
Cryptocrystalline Quartz (SiO2 with Manganese or Iron Oxide inclusions)
Graphite-rich schist (probable graphite flake)
Graphite (C) in graphitic schist; possibly graphite-bearing phyllite
Jasper
Jasper (Silicon Dioxide, SiO2)
Green Jasper (with Quartz veining)
Jasper (Silica-rich microcrystalline variety of Quartz), formula: SiO2
Banded Chert
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (SiO2)
Greenschist
Greenschist facies rock
Possible fossilized ammonite or concretion
Indeterminate fossil specimen; possibly an ammonoid mold/cast in iron-rich sedimentary rock
Chert (and Jasper variety)
Microcrystalline Quartz (SiO2)
Chert (White/Light Tan)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Petrified Wood (Agatized/Silicified Wood)
Silicified Wood (SiO2)
Chert (Nodular)
Chert (SiO2 - Microcrystalline Quartz)
Chert Pebble with Quartz Veins
Microcrystalline Quartz (SiO2)
Chert (specifically Tan/Brown Chert)
Chert (SiO2)
Shale
Shale (fine-grained clastic sedimentary rock)
Biological Bone (Patella/Knee)
Patella (part of the Human Skeletal System)
Petrified Wood (Silicified Wood)
Silicified Wood (primarily Chalcedony/Quartz, SiO2)
Banded chert or flint pebble
Microcrystalline quartz (chalcedony), SiO₂
Fossil bone or tooth fragment
Indeterminate fossilized vertebrate bone/tooth; taxonomic identification is not possible from this blurred image
Petrified Wood
Silicified Wood (SiO2)
Quartz Geode in Chert/Limestone Matrix
Silicon Dioxide (SiO2) within Sedimentary Host Rock
Petrified Wood
Silicified Wood (SiO2)
Travertine (Tufa)
Chemical Limestone (CaCO3)
Fossiliferous Brachiopod in Shale
Brachiopoda (Phylum) preserved in Carbonaceous Shale
Petrified Wood
Silicified Wood (primarily Quartz / Chalcedony: SiO2)
Petrified Wood
Silicified Wood (SiO2)
Fossiliferous limestone / shell hash rock
Bioclastic limestone (calcarenite or coquina), dominantly CaCO₃
Note: Item is not a geological specimen
Homo sapiens (Dermal Appendage: Pilus)
Pyrite (likely)
Iron disulfide, FeS₂; possibly a pyrite-rich sulfide nodule