[en] The technique of vacuum-mounting a metallographic specimen in a mixture of black pelletized alumina and a low-temperature curing black epoxy resin provides the metallography laboratory with a very versatile and efficient mounting medium. The resulting product has all of the characteristics of a potting material of extremely high quality. The desirable characteristics include minimal mold shrinkage, minimal reflectivity from the mount surface for superior photomicrography, and abrasion resistance which results in excellent specimen edge retention