A measure of the degree to which a substance may be magnetized; the ratio k or k′ of the magnetization M or I to the magnetizing force H that is responsible for it:
The susceptibility is dimensionless but of different magnitude in the two systems:
The susceptibility is related to the magnetic permeability μ
Susceptibility in cgs units is sometimes measured in units of 10–6 (‘‘micro-cgs’’). Rock susceptibility usually ranges from 0 to 0.01 cgs units (0 to 10 000 micro-cgs) and it is often proportional to the fraction of magnetite present. See Figure M-1.