Stu, I turned a ring on the bottom then carved all but the 3 feet away with a 1/2" sanding drum on a Dremel, then blended everything in by powersanding with a 2" disk.
Bill, the marbleing is a result of grafting English Walnut to Black Walnut.
This is from Woodfinder.com.
"the common name "claro walnut" is usually used to refer to the wood cut from the lower bole (stump) of orchard walnut trees, especially on the West coast of the US. These trees are a mixture of species, created by grafting an English walnut (Juglans regia) scion to a rootstock of one of our native walnut species -- either black walnut (Juglans nigra) or California walnut (Juglans hindsii). The wood near the graft tends to be variegated in color, with beautiful marble-like, dark brown and tan swirls in the figure. It is a favorite wood for making gunstocks."