Rock & Mineral Encyclopedia

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

Unakite

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

A hollow rock nodule whose interior cavity is lined with inward-pointing crystals such as quartz, amethyst, or calcite.

The principal iron ore, a heavy iron oxide ranging from metallic silver-gray to earthy red, always leaving a tell-tale red-brown streak.

A bright red mercury sulfide, the chief ore of mercury and the historic source of the pigment vermilion.

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

Clear or smoky quartz threaded with golden to reddish needles of rutile, also poetically called Venus hair stone.

A group of silicate gemstones best known for deep red but spanning nearly every color, including green tsavorite and orange spessartine.