You're lucky I'm really cheap.. I've done a lot of research on 'alternative' black gravels...
First, try to call everywhere you can (pool supply stores, hardware stores, etc) to try to find this-
in S-grade black. It's pretty dusty, so wash it well in warm water, but it's magnificient after it's cleaned.
T-Grade is a little larger (but smaller than most aquarium gravels)
It's $7-20 for 50Ib bag
This link might be able to help you- 3M.com Redirect Page
If no such luck, then call sports supply stores and look for 'Soil Master Select' or 'Turface'
Both also require rinsing, but have the advantage of being decent for planted tanks (if you decide to go that route) They're available in a few colors.. There might be a black, but I know there's a very natural-looking dark gray.
"SMS' in Charcoal-
Wait, aw... it's been discontinued. Might still find it somewhere.
Turface Gray- also discontinued.
Price varies wildly depending on the store.... Still way cheap though.
Finally, as a last resort option...
If you don't want any soft-bellied fishes, contact asphalt and contruction companies to find 'Black Beauty'. It's an aggregate used in sandblasting, but is totally inert.. It's not as course as you'd think, but definately too rough for cories or loaches, and should not be used with cichlids that sift sand.
It definately has a 'sparkle' from the quartz... but here's a pic. I'd reccomend 'fine' or 'extra fine' grades
It's about $8 per 50 pounds.. other than the fish restrictions, it's completely safe for other species (as far as I know.) I've seen it in Discus
show tanks and it's pretty amazing.