A hard to find and very little used 3 inch wide RH PREYDA surgical black Arkansas sharpening stone.

This largest size (3 by 8 by 1/2 inch) stone is no longer produced by RH PREYDA.

'Prized by craftsmen worldwide, Arkansas novaculite is the only known substance that can sharpen a blade and polish it as well.  100% natural, cut to size and skillfully finished to ensure precise flatness.'

Fitted in its original wooden box with trade mark and non-slip silicone base insert.

Please see images.