Answer :
The title of the world's sharpest cutter is often attributed to obsidian knives, which can be honed to a blade edge thinner than a single molecule, providing an incredibly precise cut. These knives are crafted using a natural volcanic glass that breaks with a conchoidal fracture, creating edges sharper than even the finest steel blades. While obsidian knives hold the record for sharpness, in the realm of man-made objects, the sharpest would be a tungsten needle created at the University of Alberta, sharpened to a single atom's width at its finest point.
Answer: Water
Explanation: when we reliase the water in 0.5 diameter and high force it can cut the Diamond also