Rock & Mineral Encyclopedia

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

Lodestone

A naturally magnetized variety of magnetite that attracts iron, historically used as the first magnetic compass.

A naturally magnetic black iron oxide and a major iron ore; strongly magnetic specimens are known as lodestone.

A soft metamorphic rock made of talc and magnesite or dolomite, formed by hydrothermal alteration of ultramafic rocks.