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

Relatively plentiful in areas where you can find it, pretty easy to shape, you can use the really sharp pieces formed from making other tools to make small things like arrowheads and knives and most importantly it can become one of the sharpest objects in history. Under a microscope I’ve been told that if you cut an individual cell with an obsidian scalpel you get a clean cut if you cut it with a metal implement it looks like a chainsaw ripped it apart