Magnetite (Lodestone)

Physical Properties

Hardness (Mohs): 5.5-6.5; Color: Iron-black to dark grey; Luster: Metallic to submetallic; Crystal Structure: Isometric (often octahedral); Specific Gravity: 5.1-5.2

Formation & Geological History

Forms in igneous, metamorphic, and sedimentary environments. Typically crystallizes from cooling magma or during high-grade metamorphism. Can also be found as placer sand deposits.

Uses & Applications

Major ore of iron for steel production. Used as a toner in photocopiers, in the chemical industry as a catalyst, and historically in compasses. Some specimens used for therapeutic jewelry or mineral collecting.

Geological Facts

Magnetite is the most magnetic of all naturally occurring minerals. Naturally magnetized pieces called lodestones served as the world's first compasses.

Field Identification & Locations

Identify in the field by its strong attraction to magnets (or its ability to act as a magnet itself). Leaves a black streak when rubbed on a porcelain plate and has a distinct heavyweight feel relative to its size.

Identified on: 5/19/2026

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