The Diamond Pacific Tool Company produces an outstanding line of grinding wheels for the industry. While they have several lines the two best known lines are the steel Galaxy Wheel which is mostly designed for rougher work and the softer Nova Wheel which are softer and for finishing stones to a high polish.
These wheels are considerably more durable that the silicon carbide grinding wheels bu DO require lubrication with water. They are not intended to be used dry.
Galaxy wheels are designed to quickly and cleanly remove material while being some of the most durable wheels on the market.
Nova wheels are designed to complete the grinding and smoothing process and produce an excellent polish on most stones. For both types of wheels you are advised to move your stone back and forth while grinding and polishing to ensure equal wear on all parts of the wheels.
Please note that both Galaxy and Nova wheels are manufactured for 1" drive shafts and while adapter chucks are available they are not part of the basic Galaxy or Nova wheel so would need to be ordered separately.