Rock & Mineral Encyclopedia

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

Ironstone

An iron-rich sedimentary rock, often heavy and rusty-weathering, historically mined as a major source of iron ore.

A striking color-zoned tourmaline with a pink center and green rind, resembling a slice of watermelon when cut across the crystal.

The green variety of tourmaline, also called verdelite, ranging from bright grass green to deep forest tones colored by iron.

A soft lithium-bearing mica with a lilac to purple color and pearly, flaky sheen, an important ore of lithium.