Carbon Fiber knife

Use alchemy to make it a diamond

Badass. Not as expensive as I thought they would be.

Obsidian is still sharper

$80 for a novelty knife? Yeah, I'll pass.

What most people don't realize about "carbon fiber" is that what they are actually talking about is a "carbon fiber composite material". Carbon fiber on it's own is more like cloth (in fact it starts out as cloth, which is then pyrolyzed ie. heated in a chamber with no oxygen). The stiff carbon fiber composite most people are thinking of is impregnated with an epoxy resin, this confers strength by the carbon fiber reinforcing the resin, and by the resin keeping the fibers from rubbing together and breaking. All this to say that, at the edge of that knife you basically have only epoxy (brittle resin with only traces of carbon fiber), it will NOT hold an edge... it will go dull after the first use.