Why is obsidian used for so many weapons even though it is very fragile?

Question

I’ve been coming across videos of people breaking obsidian chunks to make arrowheads but could never find the answer why it could be broken with light hits with a rock, and then not break when in use with said weapon.

In: 564

Answer 1

Razors are also extremely fragile but extremely sharp at the same time. If you make a very sharp arrow or spear point you only need it to be effective once. If you recover the point you can easily sharpen it again with the same methods as the original construction. If that was a modern razor sharp arrow tip you would need to replace the tip instead of just perfecting the edge, so it’s arguably better if you want to hunt regularly.