@kepano whoa that is sharp!

@kepano and it gets that edge from knapping rather than from abrading.

It's crazy to think that sometime in prehistory, some ancient hominid banged two rocks together and created a tool whose sharpness we have never been able to exceed ever since. But it is true.

@kepano for those like me who did not know what obsidian is: Obsidian is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is hard, brittle, and amorphous; it therefore fractures with very sharp edges. In the past, it was used to manufacture cutting and piercing tools, and it has been used experimentally as surgical scalpel blades. https://en.wikipedia.org/wiki/Obsidian