Thanks everyone. This wood was sitting for quite a while in my stash pile of waxed blanks. I had no idea it would end up this nice. Mulberry is a great turning wood, but is definitely more fun to turn when green. It becomes not unlike in hardness to its look-alike, osage orange when its been sitting in a hot shed for a few years. Still, dry burls can be fun to turn in another way--if the wood is sound, and you're careful with light cuts and very sharp tools, the surface finishes beautifully.