Limestone
Calcium Carbonate (CaCO3)
Category
Browse man made composite (lithified equivalent of sedimentary) specimens identified by the Rock Identifier community.
Limestone
Calcium Carbonate (CaCO3)
Milky Quartz
Silicon Dioxide (SiO2)
Red Jasper
Silicon dioxide (SiO2) with iron oxide impurities
Ferruginous Quartz
Quartz (Silicon Dioxide, SiO2) with iron oxide inclusions
Ironstone Concretion / Limonite Node
Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)
Sand Dollar (Fossilized or Calcium Carbonate Skeleton)
Clypeasteroida (Order)
Jasper
Jasper (Cryptocrystalline variety of Quartz, SiO2)
Chert / Jasper
Silicon Dioxide (SiO2)
Obsidian
Obsidian (volcanic glass)
Rhyolite Cross Pendant
Rhyolite (High-silica volcanic rock)
Carnelian Agate
Carnelian (Silicon Dioxide - SiO2)
Quartz (likely Milky Quartz or Chalcedony)
Quartz (SiO2 - Silicon Dioxide)
Tumbled pale quartz/chalcedony fragment
Quartz (SiO₂), possibly microcrystalline chalcedony
Milky Quartz
Silicon Dioxide (SiO2)
Granite or granitic gneiss pebble
Felsic granitoid, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph
Gneiss
Gneissic Metamorphic Rock
Pyrite
Iron Sulfide (FeS2)
Red Sandstone
Arenite (with Iron Oxide)
Sandstone (Quartzose Sandstone)
Clastic Sedimentary Rock (primarily SiO2 with Fe2O3 staining)
Sandstone (Ferruginous)
Arenite (primarily SiO2 with iron oxide cement)
Red Jasper (Quartzite)
Silicon Dioxide (SiO2) with iron oxide inclusions
Jasper Agate
Chalcedony (Silicon Dioxide - SiO2)
Chert (Flint Nodules)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Muscovite Schist
KAl2(AlSi3O10)(OH)2 (Muscovite) in Schist Matrix
Shale (possibly)
Shale (fine-grained clastic sedimentary rock)
Sandstone
Arenite (primarily SiO2 with trace Fe2O3)
Sandstone (likely a river or beach pebble)
Sandstone (a clastic sedimentary rock)
Weathered granite or granitic pebble
Granite; chiefly quartz, alkali feldspar, plagioclase, and minor mica/amphibole
Quartz (Chert/Chalcedony Variety)
Silicon Dioxide (SiO2)
Tumbled blue-green stone, likely chrysocolla or dyed chalcedony
Probable chrysocolla (hydrated copper aluminosilicate; variable composition), though appearance could also represent dyed chalcedony
Tumbled green aventurine (probable)
Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions
Sandstone
Clastic Sedimentary Rock
Fossil Coral
Coral Limestone (a type of biogenic sedimentary rock)
Quartz-rich gneiss
Banded quartz–feldspar–mica gneiss; commonly containing biotite and muscovite
Chert Concretion / Nodule
Microcrystalline Quartz (SiO2)
Lepidolite Bracelet
Lepidolite (K(Li,Al)3(Si,Al)4O10(F,OH)2) often in Quartz matrix
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (primarily SiO2)
Sandstone
Arenite (SiO2 based)
Sandstone
Arenite (primarily SiO2)
Sandstone
Clastic Sedimentary Rock (primarily SiO2)