Buck Coarse Diamond Pad Sharpener Buck Coarse Diamond Sharpening Stone. The coarse surface is perfect for quickly knocking off burrs or bringing back a dull edge. The stone can be used wet or dry. As with most Diamond Stones, do NOT use oil as a lubricant. Just a couple drops of water is all that’s required to keep the surface of the stone lubricated and a quick rinse when you’re done will flush away any metal from the sharpening.