... tools for various stones, fine glass, ceramic and magnetic materials, etc.MGD80:Consist of blocky cubo-octahedral crystals. ... to grind and polish stones, ceramic, glass and magnetic materials, etc.MGD50:Medium strength, contain comparative regular crystals ... , abrasive wheels to process medium load materials, like cemented carbide, ceramics, magnetic materials, glass, etc.MGD40, MGD30:Slightly friable ...