A diamond band saw is used for cutting glass, tile, and stone in a manner similar to a woodworking band saw. The blade is a diamond-bonded steel band that has a thin kerf and allows curves within the limits of blade flex. Unconventional Lapidarist has the Inland Diamond Band Saw on sale right now for $228.76.
Gentler and less wasteful than a coarser saw, opal cutters will often use a diamond band saw to reduce waste. The cut is done wet with the integral coolant system. Unsurprisingly, it can do duty as a regular band saw with wood or metal cutting blades.
Inland Diamond Band Saw [store.unconventionallapidarist.com]