Rock & Mineral Encyclopedia

Search and identify 1,000+ rocks, minerals, crystals, and gemstones — with properties, formation, colors, hardness, and how to tell them apart.

Mustard Jasper

A warm mustard-to-ochre yellow jasper colored by iron, valued by lapidaries for its rich, earthy golden tone.

A cream-colored spotted stone resembling a Dalmatian dog, made of feldspar and quartz dotted with dark mineral grains.

A dense, opaque black variety of microcrystalline quartz historically used as a touchstone for testing precious metals.

A green-and-red ornamental stone of epidote and red piemontite or iron oxide, named for its dragon-skin coloring; not a true jasper.

An altered granite mottled pink and green from feldspar and epidote, popular as a tough, colorful ornamental rock.

A schist derived from clay-rich sediments, rich in mica and often bearing index minerals like garnet, staurolite, or kyanite.

A rare Australian jasper from the Pilbara with bold red, yellow, and black abstract patterns, prized by collectors.

An Australian green rhyolite with eye-like orbs and earthy patterns marketed as jasper, evoking dense rainforest foliage.

A translucent Wyoming chalcedony filled with delicate black manganese dendrites that resemble tiny ferns, moss, or starbursts.

A hard, dark, poorly sorted sandstone with a muddy matrix, typically deposited by underwater turbidity currents.

The most common sedimentary rock, a fissile mudrock of compacted clay and silt that splits into thin layers.

A translucent common opal from the Andes prized for its serene blue to blue-green color, usually cut into cabochons and beads.

Natural emerald crystals still embedded in their host rock, prized as mineral specimens that show how the gem grew in place.