Grit for a rock tumbler
What makes high quality rock tumbling grit
The material hardness of the grit is of critical importance. This is why Silicon carbide is preferred because it is a very
hard substance. On the MOHS scale, which measures the hardness of a material from 1 to 10, silicon carbide is about 9+, so it can cut agate, jasper, and
quartz, which are hard rocks, very effectively.
Grit Shape is Key
You need grit to be angular, not rounded: Good grit breaks into sharp, angular particles instead of smooth
spheres. This characteristic allows grit to continues to “bite” or “cut” into the rock instead of just burnishing it. The longer the grit can remain in this angular form the more grit will accomplish rounded and smoothing rough edges of rock.