Magnetite is a natural magnet, hence its name. This is a distinguishing characteristic of the mineral.

Magnetite is a common accessory mineral in igneous rocks and is also found as a detrital mineral, particularly on the beaches west of Auckland (black sand).


Chemical composition - Fe 3O 4
Hardness - 5.5-6.5
Specific gravity - 5.2
Transparency - Opaque
Colour - Black
Streak - Black
Lustre - Metallic
Cleavage/fracture - Non-existent / conchoidal
Crystal habit/mode of occurrence - Prismatic (typically octahedral but rarely rhombododecahedral) / massive, granular

Other specimens - Click the thumbnails to enlarge