Chert (Flint) with Chalk Cortex
Microcrystalline Quartz (SiO2)
Category
Browse biogenic material specimens identified by the Rock Identifier community.
Chert (Flint) with Chalk Cortex
Microcrystalline Quartz (SiO2)
Granite
Granite (Feldspar-Quartz-Mica Intrusive)
Chert (Jasper/Chalcedony)
Microcrystalline Quartz (SiO2)
Blue Apatite
Apatite (Ca5(PO4)3(F,Cl,OH))
Chert
Opaline or Microcrystalline Jasper/Chert (SiO2)
Chert (Honey Chert / Flint)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (SiO2)
Basalt with Epidote (Greenstone)
Epidote-bearing Metabasalt
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Chert (and Agate/Chalcedony)
Microcrystalline Quartz (SiO2)
Diamond
Carbon (C)
Chalcedony (Agate Pebble)
Silicon Dioxide (SiO2)
Chert (often called Flint when dark)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Chert (Nodule)
Silicon Dioxide (SiO2)
Coquina
Bioclastic Limestone
Banded Calcite (often sold as 'Mexican Onyx')
Calcium Carbonate (CaCO3)
Chert (Chert Nodule)
Microcrystalline quartz (SiO2)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Tufa
Calcareous Tufa (CaCO3)
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Limonite (Iron Ore)
FeO(OH)·nH2O
Petrified Wood
Silicified Wood (SiO2)
Chert (Flint variety)
Chert (Cryptocrystalline Quartz, SiO2)
Quartz-veined Limestone
Sedimentary limestone with quartz/calcite veinlets
Murex Fossil
Muricidae (Calcium Carbonate fossilization)
Chert (Jasper/Flint variety)
Microcrystalline Quartz (SiO2)
Limestone
Calcium Carbonate (CaCO3)
Tumbled green aventurine
Quartzite dominated by quartz (SiO₂), with green mica/fuchsite inclusions
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Red Sandstone
Ferruginous Sandstone (SiO2 with Fe2O3)
Tumbled orange chalcedony (likely carnelian)
Microcrystalline quartz, SiO₂; iron-bearing variety commonly termed carnelian
Quartzite or Quartz Vein Material
SiO2
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)
Chert (often called Flint or Jasper)
Cryptocrystalline quartz (SiO2)
Limestone Gravel
Calcium Carbonate (CaCO3)
Likely weathered quartz-rich stone
Probably quartz-bearing sandstone or milky quartz; exact identification requires testing
Basalt River Pebble
Basalt
Diamond (or Simulant)
Carbon (C)
Diamond (Faceted)
Carbon (C)
Basalt (River Pebble)
Basalt
Diamond
C (Carbon)
Granite Sand and Gravel Mix
Phaneritic Felsic Igneous Plutonic Assemblage