Yes, from everything I have read it is rare and very expensive. For such small boards they really are heavy. I tap on the boards it sounds like I'm tapping on slate.
This is from The Wood Database:
Common name: Snakewood, Letterwood
Scientific name: Brosimum guianensis (syn. Piratinera guianensis)
Distribution: Coastal regions of northeast South America
Tree size: 65-80 ft (20-25 m) tall, 6-12 in (15-30 cm) trunk diameter
Average dry weight: 73 lbs/ft3 (1,170 kg/m3)
Janka hardness: 3,800 lbf (16,900 N)
Workability: Being closely related to Bloodwood, Snakewood shares many of the same working properties; namely, the wood is extremely dense, and has a pronounced blunting effect on cutters. Snakewood also tends to be quite brittle and can splinter easily while being worked. Despite the difficulties of working it, Snakewood turns well and finishes to a high polish.
This from The Woodbox:
Uses: Given Snakewood lumber's extreme difficulty to acquire it is rarely used for anything other then small craft work, particularly for knife handles. snakewood has a very tight exotic figure that works wonderfully on the small surface area of a knife handle.
The Tree: Snakewood is a truly exotic species, and probably one of the most difficult species to find. It grows irratically in South America. Typically, it is a very small tree, and only show the wonderful figure in a small quantity of the wood, and then rarely evenly spread across the entire face of the board.
Finishing: The tight grain of the wood makes finishing relatively easy with traditional lacquers, although I have known some knife makers that have stabilized this wood in a small vacuum chamber to prevent minor absorption of body oils from constant usage... this tends to extend the life of the finish.
Machining: Cuts and turns like a hard maple, with a clean fine texture. Snakewood lumber needs industrial sandpaper, and a bit of patience to work up the grits if you wish to get that really silky finish.
This is about the best info on finishing snakewood that I've seen so far. Unfortunately, I don't have very much of this lumber so practice cuts really aren't an option. That's the reason I've been researching and asking questions.
Thanx for your input,