I don`t know if you would be aware, but didn`t surgeons use or still use, pieces of flint for fine procedures because flint is sharp to the molecular level, not micron as would be steel?
No, I`m not making that up...read it somewhere within the last five years..
heart surgeons IIRC, the edge of an obsidian blade can be exactly one SiO2 molecule thick.....cant sharpen steel that fine.......but it does loose its edge much faster than steel.....
