Rock & Mineral Encyclopedia
Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.
Rogue River Jasper
An Oregon picture jasper from the Rogue River area showing earthy scenic patterns in tan, brown, gold, and cream.
mineral
Rock Gypsum
A soft sedimentary evaporite made of massive gypsum, deposited when sulfate-rich seawater or lake water evaporates and concentrates.
sedimentary
Asphalt Rock
A porous sedimentary rock naturally saturated with bitumen, dark, tarry-smelling, and historically mined for paving.
sedimentary
Coral Rock
A porous limestone built from the calcium carbonate skeletons of corals and reef organisms, the lithified remains of ancient or modern reefs.
sedimentary
Dalmatian Stone
A cream-colored feldspar-and-quartz rock peppered with dark spots, named for its resemblance to a Dalmatian dog.
igneous
Conglomerate
A coarse sedimentary rock of rounded pebbles and gravel cemented in a finer matrix, recording ancient rivers and beaches.
sedimentary
Kentucky Agate
The official state rock of Kentucky, a banded agate famous for striking deep-red and black fortification patterns.
gemstone
Cherry Creek Jasper
A landscape-patterned Chinese jasper prized for warm cherry-red, cream, and green bands resembling painted scenery.
mineral
Montana Garnet
Montana Garnet is red almandine recovered from Montana placer gravels, often alongside the state's famous sapphires.
gemstone
Hells Canyon Jasper
A warm earth-toned jasper from the Hells Canyon region of the Oregon-Idaho border, prized for brecciated browns, reds, and creams.
gemstone
Montana Moss Agate
A translucent chalcedony from Montana filled with black and red dendritic inclusions that look like moss, ferns, or scenic landscapes.
gemstone
Tintenbar Opal
Rare precious opal from Tintenbar in northern New South Wales, Australia, occurring in volcanic basalt rather than sedimentary rock.
gemstone
Deschutes Jasper
A prized Oregon picture jasper from the Deschutes region known for soft scenic landscapes in cream, tan, and blue-gray.
mineral
Crowley Ridge Agate
Agate found in the gravels of Crowley's Ridge in northeastern Arkansas, a stream-transported banded chalcedony.
gemstone
Sandstone
A clastic sedimentary rock made of cemented sand grains, often quartz, recording ancient beaches, deserts, and rivers.
sedimentary
Oolite
A limestone made of tiny spherical ooids, resembling fish roe, formed in warm, agitated shallow seas.
sedimentary
Limestone
A soft carbonate sedimentary rock made mostly of calcite, often packed with marine fossils and prone to forming caves.
sedimentary
Ironstone
An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.
sedimentary
Coquina
A soft, porous limestone made of loosely cemented shell and coral fragments, used as a coastal building stone.
sedimentary
Pisolite
A sedimentary rock built from pea-sized concentric spheres called pisoids, often carbonate but sometimes iron or aluminum-rich.
sedimentary
Soapstone
A soft, talc-rich metamorphic rock with a soapy feel, easily carved and highly heat-resistant for cookware and sculpture.
metamorphic
Lapis Lazuli
An intensely blue metamorphic rock of lazurite flecked with golden pyrite, prized for millennia as a gemstone and ultramarine pigment.
metamorphic
Greenstone
A general field term for green, low-grade metamorphosed basaltic rocks colored by chlorite, epidote, and actinolite.
metamorphic
Verdite
A rich green, fuchsite-rich metamorphic rock from southern Africa, prized as a carving and ornamental stone.
metamorphic