Chert (Flint)
Chert (SiO2)
Category
Browse organic (non rock) specimens identified by the Rock Identifier community.
Chert (Flint)
Chert (SiO2)
Sandstone (Ferruginous)
Clastic Sedimentary Rock (Sandstone)
River Pebble (Greywacke or Quartzite-rich Sandstone)
Lithic Sandstone (primarily SiO2 with rock fragments)
Likely basalt (possibly a dark beach pebble)
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Chert (Jasper type)
Microcrystalline Quartz (SiO2)
White Precious Opal
Hydrated Silica (SiO2·nH2O)
Turritella Agate / Fossiliferous Limestone
Elimia tenera in Chalcedony/Calcite Matrix
Chert / Chalcedony
Silicon Dioxide (SiO2)
Anthracite Coal
Anthracite (Carbon-based sedimentary-metamorphic rock)
Chert (Flint)
Microcrystalline Quartz (SiO2)
Quartzite
Quartzite (primarily SiO2)
River Siltstone Pebble
Siltstone (primarily composed of silica and clay minerals)
Diorite (Spotted or Dalmatian Stone pattern)
Diorite
Quartz Pebble
Silicon Dioxide (SiO2)
Quartzite River Rock
Metaquartzite (majorly SiO2)
Quartzite
Quartzite (SiO2)
Sandstone
Sandstone (principally SiO2/Silicon Dioxide)
Chert (specifically Jasper/Flint)
Microcrystalline Quartz (SiO2)
Chert (and Flint)
Cryptocrystalline Quartz (SiO2)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Serpentine (Nephrite-like Serpentine)
Serpentinite (Hydrous magnesium iron phyllosilicate)
Shale
Fissile mudrock (composed primarily of clay minerals and quartz)
Geode (unopened)
Chert / Chalcedony Geode (SiO2)
Ferruginous Quartzite (Red Quartzite)
Quartzite (primarily SiO2 with Fe2O3 inclusions)
Anthracite Coal
Anthracite (Carbon-based metamorphic rock)
Quartzite
Quartzite (SiO2-rich metamorphic rock)
Weathered agate or chalcedony nodule
Microcrystalline quartz (SiO₂), likely agate/chalcedony with iron-oxide staining
Pink Quartzite Pebble
Quartzite (SiO2)
Quartzite
Quartzite (composed primarily of SiO2)
Fossiliferous Limestone (Coquina)
Biogenic Limestone (Calcium Carbonate, CaCO3)
Obsidian
Volcanic Glass (Amorphous SiO2)
Quartzite Cobble (Iron-stained)
Quartzite (SiO2)
Conglomerate
Conglomerate (SiO2, Al2O3, Fe2O3, CaCo3)
Quartz Geode
Silicon Dioxide (SiO2)
Quartzite
Metamorphic Quartzite (SiO2)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Chert (Polished/Tumbled)
Silicon Dioxide (SiO2)
Quartzite
Quartzite (SiO2)
Amber
Succinite (formula varies, primarily C10H16O)
Glauconitic Sandstone
Glauconitic Sandstone (contains (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)
Chert / Flint
Cryptocrystalline Quartz (SiO2)