These bowls range from about 3″ to about 7″ diameter.
The black staining was in the log – from water getting into cracks in the wood while it was still on the tree. I did fill a few cracks with black epoxy. Finish is walnut oil.
Two of the bowls have darker color (upper right and the natural-edge one). These were turned about a month before the others, so have had that much longer to darken (which is natural with mulberry).