For shaping gemstones, I’ve found diamond milling tools especially useful for profiling, grooving, or removing material from areas a standard lap can’t reach.
Tool diameter, diamond grit, bond, and feed rate all affect the finish. With smaller profiles, keeping the tool stable and using light, consistent pressure can make a big difference in controlling chipping and maintaining the intended shape.
This reference covers diamond milling tools, including diamond routers, profile tools, milling tools, and related applications.
What type of gemstone work have you found benefits most from diamond milling or profiling tools?