Magnetic susceptibility values for common mineral and rock types (Sharma, 1997).
Mineral or rock type Magnetic susceptibility (k x 10−6 SI)
Granite (with magnetite) 20–40,000
Slates 0–1200
Basalt 500–80,000
Oceanic basalt 300–36,000
Limestone (with magnetite) 10–25,000
Gneiss 0–3000
Sandstone 35–950
Hematite (ore) 420–10,000
Magnetite (ore) 7×104–14×106
Magnetite (crystal) 150×106
A magnetic susceptibility value describes how much a material becomes magnetized when exposed to an applied magnetic field, essentially indicating its tendency to be attracted or repelled by a magnet; it's a dimensionless quantity calculated by dividing the magnetization of a material by the applied magnetic field strength, with a positive value signifying paramagnetic behavior (attracted to a magnetic field) and a negative value indicating diamagnetic behavior (repelled by a magnetic field).
"magnetic susceptibility" measures how easily a material becomes magnetized when exposed to an external magnetic field, whereas "magnetic permeability" describes how readily a material allows magnetic field lines to pass through it, essentially indicating its ability to form an internal magnetic field within itself when exposed to an applied magnetic field; in simpler terms, susceptibility is a measure of how much a material is magnetized, while permeability is a measure of how well a material allows magnetism to pass through it.
A material's permeability indicates how easily an external magnetic field can induce an internal field in the material. The stronger the internal field, the stronger the force of attraction. A material's permeability is not constant but rather changes based on several factors.