Chert (Flint)
Chert (Cryptocrystalline Silica, SiO2)
sedimentary
Category
Organic (Non Rock)
Browse organic (non rock) specimens identified by the Rock Identifier community.
Learn about Organic (Non Rock) in the encyclopedia
View all →
Chert (Gravel)
Chert (Microcrystalline Silicon Dioxide, SiO2)
sedimentary
Jasper
Silicon dioxide (SiO2)
sedimentary
Chert (Nodule)
Silicon Dioxide (SiO2)
sedimentary
Chert (often called Flint in dark varieties)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Fossils in Limestone (Crinoid / Marine Invertebrate Fossil)
Fossiliferous Limestone (containing Crinoidea / Brachiopoda)
fossil
Common Opal (Green Opal)
Hydrated Silicon Dioxide (SiO2·nH2O)
mineral
Pumice
Pumice (Amorphous volcanic glass)
igneous
Sandstone
Sedimentary Clastic Rock (Quartz Arenite)
sedimentary
Likely chert or flint
Microcrystalline quartz (SiO₂), commonly called chert; exact identification requires testing
sedimentary
Coral Fossil (Hexagonaria)
Hexagonaria sp. (Silica-replaced)
fossil
Coal
Bituminous coal (Complex organic sedimentary rock)
sedimentary
Gray River Pebble (likely Limestone or Siltstone)
Sedimentary Rock (Calcium Carbonate or Siliciclastic)
sedimentary
Quartzite
Quartzite (primarily SiO2)
metamorphic
Greenstone / altered mafic rock
Likely chlorite–actinolite metabasalt (greenschist); exact identification requires testing
metamorphic
Obsidian
Obsidian (Volcanic Glass, SiO2)
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Silty Shale or Mudstone
Siltstone/Mudstone (Clastic Sedimentary Rock)
sedimentary
Chert (Polished/Worn)
Microcrystalline quartz (SiO2)
sedimentary
Red Quartzite River Rock
Metamorphic Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Pyrite in Slate or Shale
Iron Sulfide (FeS2) in Argillaceous Matrix
mineral
White limestone or chalky carbonate rock
Calcite-rich limestone; possibly chalk (CaCO₃)
sedimentary
Fossilized Bone
Permineralized Bone (Vertebrate Fossil)
fossil
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
sedimentary
Shale fragment
Shale (Laminated Mudstone)
sedimentary
Siltstone with Fossil Cast
Sedimentary Rock (Siltstone / Fine-grained Sandstone)
sedimentary
Pyrite in Shale
Iron Sulfide (FeS2) in Sedimentary Matrix
mineral
Obsidian
Obsidian (principally SiO2)
igneous
Quartzite River Rock
Quartzite (primarily SiO2)
metamorphic
Chert Nodule
Chert (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Banded Chert
Silicon Dioxide (SiO2)
sedimentary
Sandstone (with carbonaceous plant fragments)
Arenite (composed primarily of SiO2)
sedimentary
Fossil Shell (Brachiopod or Mollusk)
Phylum Brachiopoda or Class Bivalvia (e.g., Mucrospirifer or similar genus)
fossil
Blue Obsidian
Volcanic Glass (SiO2 with inclusions)
igneous
Iron Slag (Industrial Byproduct)
Anthropogenic Vitrification Product/Ferrous Slag
Mineral-like Industrial Smelting Waste
Chert / Chalcedony Nodules
Microcrystalline Quartz (SiO2)
sedimentary
Graphite-rich schist (likely graphite ore)
Graphite-bearing schist; predominantly graphitic carbon (C) with mica, quartz, and possible feldspar
metamorphic
Quartzite
Quartzite (primarily SiO2)
metamorphic
Limestone
Calcium carbonate (CaCO3)
sedimentary
Siltstone with flute casts or scratch marks
Clastic Sedimentary Rock (Siltstone/Fine-grained Sandstone)
sedimentary