Thanks John...that's man-made Veriscite Tru-stone (aka Recon Stone). It's difficult to find in sizes larger than a pen blank. The link below is where I get it currently. They will cut it into thin sheets for you, so there's not much waist. I usually buy 1/8" thick slabs. If you decide to buy some, ask for the soft (HSS tool turn-able) type. The hard version of Tru-Stone in really hard, and only turn-able with carbide cutters.