Go to an auto parts store or Woodcraft for emery paper.
400, 600, 1200 & 2000 grit will get you to the polishing stage
again. Washing the stone when you move up to a smaller size particle.
Rough is 400/ 2000 being very tiny particle.
Any lapidary polish will work after you run thru each grit size on
leather, cloth. Or even printing paper if flat.
Moonstone is very soft- as you found out. Feldspar is found in a huge
variety of color. Around here in Central Texas it is pink and a major
component in pink granite.
Your local gem and mineral club will show you how to re-polish them
faster. Take a class.