Rock & Mineral Encyclopedia

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

Cloud Agate

A chalcedony agate with soft, billowing cloud-like masses of gray and white suspended in a translucent body.

A fortification agate from the Black Hills of South Dakota, known for tight, colorful banding closely related to the famous Fairburn agate.

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

A richly colored red banded agate prized by lapidaries for its deep crimson-to-brown tones reminiscent of pigeon's blood.

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