Rock & Mineral Encyclopedia

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

Itabirite

A metamorphosed banded iron formation of alternating quartz and iron-oxide layers, mined as a major iron ore.

A fiery jasper whose red, orange, and yellow plumes lick across the stone like flames against an earthy background.

A warm orange-to-red variety of chalcedony quartz colored by iron oxide, used since antiquity for seals, beads, and cabochons.

A microcrystalline quartz jasper marked by small concentric ring or eye patterns that resemble the eyes of birds.

A dark green jasper-chalcedony speckled with red iron-oxide spots, classically known as bloodstone or heliotrope.