Mineral

Formula

Field Strength (kGauss)

Ferromagnetic

Magnetic

Fe₃O₄ (Black powder)

1

Pyrrhotite

Fe₇S₈ (Black powder)

0.5 - 4

Paramagnetic

Ilmenite

FeTiO₃

8 - 16

Siderite

FeCO₃ (Black powder)

9 - 18

Chromite

FeCr₂O₄

10 - 16

Hermatite

Fe₂O₃ (Black powder)

12 - 18

Wolframite

(Fe, Mn)WO₄

12 - 18

Tourmaline

Al₆B₃Fe₃H₁₀NaO₃₁Si₆

16 - 20