Crumble is a spell which turns either a mineral or organic matter into small particles. It is generally used to mill oat corn without the use of a mill, or to break down stones that are found in a field while ploughing.
The spell converts an item into small particles over the course of several seconds.
The spell causes a grinding sound while being cast, which can be quite loud. The caster may have sore muscles, especially in the shoulders, after casting it.