Gneiss
Metamorphic rock of high-grade regional metamorphism
Category
Browse sedimentary rock (specifically a chemical sedimentary rock, or a chert if considered purely mineral aggregate) specimens identified by the Rock Identifier community.
Gneiss
Metamorphic rock of high-grade regional metamorphism
Quartz Pebble
Quartz (Silicon Dioxide, SiO2)
Graywacke with Quartz Vein
Lithic Sandstone (Graywacke)
Fossiliferous Limestone
Calcareous biomicrite / Bioclastic limestone
Brown Sandstone
Arenite (primarily Quartz and Feldspar, with Iron Oxide cement)
Basalt with Limonite stains
Extrusive mafic igneous rock; Limonite (FeO(OH)·nH2O)
Dalmatian Stone
Peralkaline rhyolite with arfvedsonite (formerly incorrectly called Dalmatian Jasper)
Chert (Common Opal/Agate mixture)
Microcrystalline Quartz (SiO2)
Geode (Unopened)
Siliceous Concretion / Geode
Turquoise
Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]
Quartz Geode
Silicon Dioxide (SiO2)
Chert (variously known as Flint)
Microcrystalline quartz (SiO2)
Chert (Common Opal/Agate inclusion)
Microcrystalline Quartz (SiO2)
Sandstone (Quartzose Sandstone)
Clastic sedimentary rock (SiO2 primary composition)
Sandstone or Quartzite
Arenite (if sedimentary) / Quartzite (if metamorphic)
Limestone
CaCO3 (principally Calcite)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Geode (unopened)
Silica-filled Concretion (SiO2)
Quartz Geode with Chalcedony
Silicon Dioxide (SiO2) in Geode Form
Sandstone
Arenite
Conglomerate
Conglomerate (Detrital Sedimentary Rock)
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
Jasper (Iron-stained Quartzite/Chert)
Silicon Dioxide (SiO2) with iron oxide inclusions
Chert (Jasper)
Silicon Dioxide (SiO2)
Conglomerate
Conglomerate (clastic sedimentary rock)
Fossiliferous Limestone
Fossiliferous Calclutite / Bio-calcarenite (CaCO3)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily SiO2)
Quartz Geode
Silicon Dioxide (SiO2) in a Secondary Formation
Asphalt
Asphalt concrete (engineered material, not a naturally occurring rock/mineral in this form)
Asphalt Concrete
Bituminous Concrete / Asphaltic Composite
Jasper-Agate Conglomerate (Potentially Puddingstone)
Jasper-cemented Silicate Aggregate (SiO2)
Shale with Vein Infillings
Shale (a fine-grained clastic sedimentary rock). The veins could be Calcite (CaCO3), Quartz (SiO2), or other minerals.
Geode or Concretion
Silica-based Concretion / Quartz Geode
Red Jasper (Polished)
Silicon Dioxide (SiO2) with Hematite inclusions
Quartz Geode
Silicon Dioxide (SiO2)
Oolite (Ooid Limestone)
Ooidal Limestone (comprised of CaCO3)
Conglomerate
Conglomerate
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)
Gneiss (Gneissic Granite)
Gneiss
Dalmation Stone
Peralkaline Rock (SiO2 with Arfvedsonite)
Greywacke (River Pebble)
Greywacke sandstone with quartz veining
Gneiss
High-grade Metamorphic Gneiss