Rock & Mineral Encyclopedia

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

Bamboo Agate

An agate whose layered, segmented banding resembles the jointed stalks and leaves of bamboo.

A vivid Australian jasper-like silica stone in earthy reds, yellows, and purples, formed from silicified radiolarian sediment.

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

A prized plume agate from near Carey, Idaho, showing red, pink and black feathery plumes floating in translucent chalcedony.

A cream-colored feldspar-and-quartz rock peppered with dark spots, named for its resemblance to a Dalmatian dog.

An opaque grey-brown common opal forming nodules and concretions, historically called liver opal for its dull brownish color.

A banded, metamorphosed iron formation in which bright red jasper alternates with silvery hematite or magnetite layers.

A banded combination rock of golden tiger's eye, red jasper, and metallic hematite, formed in ancient iron deposits.

A waxy, translucent microcrystalline form of quartz that serves as the parent group for agate, jasper, carnelian, and onyx.