Even Tungsten isn't particularly hard to cut. Also truly Tungsten rings are a lot less common.
Most of the rings referred to as Tungsten rings are actually Tungsten Carbide. Tungsten Carbide rings, by comparison, is VERY hard to cut. You basically need a diamond blade/saw/grinding wheel to cut through TC.
Yet, you (gently) smash it with a hammer and it breaks to pieces. By adding a block that is a bit thicker than the finger bone, you prevent smashing your finger in the process
Most of the rings referred to as Tungsten rings are actually Tungsten Carbide. Tungsten Carbide rings, by comparison, is VERY hard to cut. You basically need a diamond blade/saw/grinding wheel to cut through TC.