Casting an obsidian blade

Obsidian is a type of volcanic glass that was frequently used to make stone tools. Obsidian stone tools, which could be knives, scrapers, arrowheads or even fish hooks, were carefully formed by chipping off flakes from a piece of obsidian. It was time consuming, but obsidian is very durable and can hold an extremely sharp edge.

In the video above the tool maker takes a more modern approach -- he melts the obsidian and tries to cast the blade. I'll leave you decide whether his approach is progress or not.