Sandstone
Arenite (primarily Quartz-rich)
Category
Browse organic material (likely a fruit or berry) specimens identified by the Rock Identifier community.
Sandstone
Arenite (primarily Quartz-rich)
Sandstone
Arenite (SiO2 primarily)
Sandstone
Clastic Sedimentary Rock (composed mostly of quartz, SiO2)
Tumbled quartz-rich pebble
Microcrystalline quartz (SiO₂), possibly weathered chert or chalcedony
Brecciated jasper (likely ocean jasper or red jasper)
Microcrystalline quartz, SiO₂, with iron-oxide pigments and breccia cement
Petrified Wood
Silicified Wood (SiO2)
Iron sulfide-rich ore, possibly pyrite-bearing gossan
Likely pyrite (FeS₂) with iron oxides/hydroxides and host rock; exact identification requires testing
Chert (Nodule)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (White Flint)
Silicon Dioxide (SiO2)
Fossilized coral or porous marine limestone
Likely fossil coral (Scleractinia), composed mainly of calcite/aragonite (CaCO₃)
Chert (Arrowhead Artifact)
Microcrystalline Quartz (SiO2)
Shale
Mudrock / Fissile Shale
Chert (specifically Flint Arrowhead)
Silicon dioxide (SiO2) - Microcrystalline Quartz
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Chert (SiO2)
Chert (Flint)
Silicon Dioxide (SiO2)
Chert (River Pebble with Liesegang Rings)
Microcrystalline Silicon Dioxide (SiO2)
Quartz (Common or Milky Quartz) with Iron Staining
Silicon Dioxide (SiO2)
Weathered flint or chert fragment
Microcrystalline quartz (SiO₂), likely chert/flint
Chert (Black Flint)
Microcrystalline Quartz (SiO2)
Chert (Chert Nodule with Cortex)
Microcrystalline Quartz (SiO2)
Petrified Wood
Silicified Wood (primarily SiO2)
Chert (River Pebble)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (Microcrystalline Quartz, SiO2)
Chert (Commonly called Jasper or Flint)
Chert (SiO2)
Sandstone (Weathered Pebble)
Arenite (SiO2 primarily)
Granite Pebble
Felsic Plutonic Rock (primarily Quartz, Feldspar, and Mica)
Glacial Quartzite Cobble
Meta-orthoquartzite (SiO2)
Magnetite-rich iron ore (probable magnetite schist)
Magnetite (Fe₃O₄) in a foliated metamorphic matrix, possibly magnetite–biotite schist
Chert (specifically Blue Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Quartzite Pebble with Pyrite Coating
SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating
Chert (Black Flint)
Microcrystalline Quartz (SiO2)
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
Tree Agate (or Moss Agate)
Dendritic Agate (Silicon Dioxide - SiO2)
Chert with Quartz Vein
Microcrystalline Quartz (SiO2)
Fossilized Coral (Petrified Coral)
Lithostrotionella (example genus) / Scleractinia
Likely weathered quartz-bearing rock fragment
Indeterminate; appears to contain quartz (SiO₂) with iron-oxide staining, possibly from quartzite, granite, or pegmatite
Possible weathered granite or gneiss
Feldspar–quartz–mica rock; exact identification is uncertain from the photograph
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Milky quartz (massive quartz)
Quartz, silicon dioxide (SiO₂)
Chert (specifically Flint or Chalcedony nodule)
Microcrystalline Quartz (SiO2)
Chert (Flint)
Chert (Microcrystalline Quartz, SiO2)