[_a_a_a_]

apparently yes. Broken glass (which obsidian is, a volcanic glass) have edges a few atoms wide beating anything manmade.

[progbits]

Yes but it is not very durable and the blade dulls quickly, hence all the effort on fancy steel blades.

[_a_a_a_]

They are fragile I've heard, and quite likely they dull quickly (don't know), but I'm not saying they're 'better' than steel; it's not a competition. Horses/courses.