Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Category
Browse mineral or sedimentary rock (with mineral inclusions) specimens identified by the Rock Identifier community.
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Tumbled Carnelian and Quartz Mix
Silicon Dioxide (SiO2) with iron oxide impurities
Carnelian (Carnelian Agate)
Silicon dioxide (SiO2) - a variety of Chalcedony
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Milk Quartz (White Quartz)
Silicon Dioxide (SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Shale
Shale
Clear Quartz (Rock Crystal)
Quartz (Silicon Dioxide, SiO2)
River Cobble (likely Sandstone or Siltstone type)
Sandstone or Siltstone (common rock types that form river cobbles)
Red Chert (Jasper)
Chert / Microcrystalline Quartz (SiO2)
Shale or Mudstone (Based on appearance)
Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)
Mookaite Jasper
Radiolarite (Silica-rich sedimentary rock featuring Hematite and Goethite)
Milky Quartz
Silicon Dioxide (SiO2)
Shale
Fissile mudstone (rich in clay minerals and quartz)
Smoky Quartz (with possible Feldspar inclusions)
Silicon Dioxide (SiO2)
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Sandstone (Weathered Pebble)
Arenite (SiO2 primarily)
Turquoise
Hydrous phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)
Sandstone (with potential iron-oxide staining)
Arenite (primarily SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Jasper (Mookaite variety likely)
Silicon Dioxide (SiO2) with iron oxide inclusions
Conglomerate
Conglomerate (Detrital sedimentary rock)
Sandstone (Ferruginous)
Ferruginous Sandstone (SiO2 with Fe2O3)
Unidentified Rock Fragment
Unknown
Turquoise (Green variety)
Hydrous phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O
Quartz Druzy Geode
Silicon Dioxide (SiO2)
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Jasper (specifically Polychrome or Desert Jasper)
Silicon Dioxide (SiO2) with iron oxide and other mineral impurities
River Pebbles (Sandstone and Quartzite)
SiO2 (Quartz) dominated clastic rocks
Geode Nodules / Chalcedony Geode
Silicon Dioxide (SiO2) - Amorphous to Cryptocrystalline Quartz
Granite Gneiss
Gneiss (High-grade regional metamorphic rock)
Sandstone (clastic)
Clastic Sedimentary Rock (primarily composed of SiO2)
Sandstone (Quartzose)
Arenite (primarily SiO2)
Leopard Skin Jasper
Jasper (Silicon Dioxide with impurities), SiO2
Jasper (Iron-stained Quartz)
Silicon dioxide (SiO2) with iron oxide inclusions
Sandstone
Arenite
Sandstone (Ferruginous)
Arenite (primarily SiO2 with Fe2O3 staining)
Gneiss
Gneiss (High-grade Regional Metamorphic Rock)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Sandstone with Iron Oxide
Arenite (SiO2 with Fe2O3 staining)
Chert / Flint
Chert (varietal name for microcrystalline quartz). Chemical formula: SiO₂
Red Jasper (Brecciated or Mottled)
Silicon Dioxide (SiO2) with iron oxide inclusions