Magnetite / Iron Ore

Physical Properties

Hardness: 5.5-6.5 on Mohs scale; Color: Black to brownish-black; Luster: Metallic to submetallic; Crystal Structure: Isometric; Cleavage: None; Specific Gravity: 5.1-5.2

Formation & Geological History

Forms in igneous rocks like basalt and granite through magmatic cooling, in metamorphic rocks through regional metamorphism, and in sedimentary deposits as black sand. Can be found in geological formations ranging from billions of years old to modern beach sands.

Uses & Applications

A major ore of iron used in the production of steel. Also used for water purification, as a toner in photocopiers, and as a magnetic pigment in paints.

Geological Facts

Magnetite is the most magnetic mineral on Earth. Naturally magnetized pieces are called lodestones, which were used as the first primitive compasses in history.

Field Identification & Locations

Identify in the field using a strong magnet (it will be strongly attracted) and checking for a black streak on a porcelain plate. Look for it in heavy sand deposits or dark, dense igneous outcrops.

Identified on: 4/7/2026

Mode: Standard