Obsidian would actually be a pretty awesome razor material, come to think of it. From Wikipedia:

>Because of this lack of crystal structure, obsidian blade edges can reach almost molecular thinness, leading to its ancient use as projectile points and blades, and its modern use as surgical scalpel blades

see also: http://en.wikipedia.org/wiki/Obsidian#Current_use

You wouldn't want to use volcanic chips, of course, but now I want to pitch this to pg. I mean, used in scalpels? Shiiiit.