I have been looking for a substitute for tropical ebony that I could use when I want a dark/black binding. I forget where I saw the reference, but through the wonder of ebay, I acquired a piece of ‘bog oak’, which is very black. Bog oak is from an oak tree that was buried in a peat bog for some thousands of years (estimate 2000-4000) where the anaerobic conditions prevent decay and the tannin and iron salts in the bog turn the oak black. This is of Russian origin, bought from a fellow in the Ukraine. Interesting, no postage meter, just slap on a whole bunch of stamps, and wrap the whole package in lots of clear tape. (If anyone wants the stamps, drop me an e-mail.)