What stone was used by Neolithic people to sharpen objects?

Neolithic people used stone tools made from various types of stone. The sharp edges of these tools were created by breaking the stone against either another stone, or causing it to break through pressure which used materials such as antler or any hard rock.

These tools were then used to sharpen other things. The best types of stone for sharp cutting edges are flint and obsidian (a type of volcanic glass).