An equation is presented which describes the conductivity (resistivity) of a wide variety of binary macroscopic mixtures as a function of the conductivities (resistivities) of the components, the volume (area) fraction of each, and two parameters. Unlike in an earlier version, the granular shape of at least one component is no longer required to be roughly spherical (circular). One parameter is the critical volume (area) fraction. The other, the exponent, is a combination of effective demagnetisation coefficients and the critical fraction. The equation, which is valid for all volume fractions, is shown to fit a variety of experimental data very well. Some deductions about the shape of the grains in the media can be made by analysing the experimental results.