Mike -- Microcrystaline wax is not a form of abrasive polish. It is a manmade wax that, as its name implies, has very small wax particles carried in a solvent. (The solvent keeps the wax soft until the wax is used, the solvent evaporates, leaving the wax particles behind.) Natural waxes consist of particles that are much larger. The micro particles in a microcrystaline wax breakup the lightwaves reflecting off of the wax, which effectively hides things like fingerprints.
You can use microcrystaline wax to make an abrasive polish by adding, as you suggested, an abrasive like diatomaceous earth and a carrier like mineral oil. However, bees wax would be cheeper.