how to make powder of hard rock

How to fix rock hard espresso powder? :p - how to make powder of hard rock ,Put it in a few layers of plastic bags. Put the bags in between two boards and hammer hard, After the "rock" is broken into smaller pieces, use you coffee grinder to grind the pieces into powder.How to Grind Stone Into Powder | SciencingGrinding stone into powder is something you might need to do for all sorts of reasons. The process of assaying ore samples for mineral content usually requires that stone be ground down to a fine powder.