... magnetic materials, etc.MGD80:Consist of blocky cubo-octahedral crystals. High impact strength and thermal stability. It is very ... etc.MGD70:It contains a high level of cubo-octahedral crystals, high strengh and thermal stability, good impact resistence. ... materials, etc.MGD50:Medium strength, contain comparative regular crystals and blocky crystals. Ideal to make grinding wheels, abrasive wheels to ...