Definitions for "Resistivity"
The electrical resistance per unit length of a unit cross-sectional area of a material, can be measured in geological materials.
The ratio of the applied voltage to the current
The resistivity R is the resistance of a unit cube with unit potential difference between a pair of faces. It varies over an immense range: from a little more than 1 in units of 10.m (which are the same as cm) for good conductors, to more than 10 24 in the same units, for the best insulators.