Black Opal
Hydrated silica (SiO2·nH2O)
Category
Browse sedimentary (base), then artificial specimens identified by the Rock Identifier community.
Black Opal
Hydrated silica (SiO2·nH2O)
Dinosaur Fossil (Tyrannosaurus rex skull replica/specimen)
Tyrannosaurus rex (fossilized in permineralized sedimentary matrix)
Sandstone (with Iron Staining)
Clastic Sedimentary Rock (primarily Quartz, SiO2)
Sandstone
Arenite (primarily SiO2)
Zebra Rock (Zebra Stone / Ribbon Stone)
Siltstone with Ferruginous Banding (Primarily Quartz, Kaolinite, and Hematite)
Picasso Stone
Metamorphosed Calcium Carbonate (Limestone)
Fossiliferous Limestone
Calcium Carbonate (CaCO3)
Fossiliferous Limestone
Biogenic Calcium Carbonate (CaCO3)
Shale
Fissile Mudstone (primarily composed of clay minerals and quartz)
Limestone
Calcium Carbonate (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Limestone
Calcium Carbonate (CaCO3)
Chert (and Quartz Gravel)
Chert (Cryptocrystalline Quartz, SiO2)
Coquina / Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate - CaCO3)
Crushed Limestone (Gravel)
Calcium Carbonate (CaCO3)
Sandstone (Quartzose Pebble)
Clastic sedimentary rock (primarily SiO2)
Sandstone (Glacial Cobble)
Arenite / Sedimentary Rock (primarily SiO2)
Sandstone (Quartz-rich Pebble)
Arenite (primarily SiO2)
Coquina with Shell Fragment
Bioclastic Limestone (composed primarily of CaCO3)
Coquina
Coquina (Bioclastic Limestone)
Chert (Iron-stained)
Microcrystalline Quartz (SiO2)
Granitoid Gneiss with Feldspar Vein
Gneiss (High-grade Metamorphic Rock) with Potassium Feldspar (KAlSi3O8)
Limestone (specifically Dolomitic Limestone)
Calcium Magnesium Carbonate (CaMg(CO3)2)
Black Jasper (Black Stone / River Pebble)
Silicon Dioxide (SiO₂), Opaque variety of Chalcedony
Chert (Nodule)
Microcrystalline Quartz (SiO2)
Conglomerate
Conglomerate (clastic sedimentary rock)
Crushed Limestone
Calcite-rich Sedimentary Rock (CaCO3)
Rainbow Hematite (Man-made/Treated)
Tumbled Hematite with Titanium/Anodized coating (Iron(III) oxide, Fe2O3)
Graphite
Graphite (Native Carbon, C)
Mica-rich Schist fragment
Mica Schist
Mica Schist
Mica Schist (primarily composed of Muscovite/Biotite)
Graphite
Graphite (Native Carbon), Formula: C
Fossiliferous Limestone
Sedimentary Calcium Carbonate (CaCO3)
Conglomerate
Conglomerate (clastic sedimentary rock)
Limestone
Sedimentary Calcium Carbonate (CaCO3)
Conglomerate
Conglomerate (Detrital sedimentary rock)
Sandstone with Manganese Dendrites/Oxide coatings
Arenite with Pyrolusite and Romanechite (MnO2)
Chalcedony with Matrix
Silicon Dioxide (SiO2)
Sandstone
Arenite (SiO2 based typically)
Limestone
Calcium Carbonate (CaCO3)
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
Quartz / Common Opal Transition
Silicon Dioxide (SiO2)