There are two main types of diamond stone styles. The more common style contains holes in the diamond surface to capture the swarf. These stones cut very fast and are very simple to use. The next type is the continuous diamond surface. These stones are preferred when you are sharpening tools with points that might get caught in the recesses of the non-continuous diamond surface. Both types of diamond stones are available in mono-crystalline and poly-crystalline diamonds. The mono-crystalline diamonds are more desirable as they will last longer.