______ diamond is used to cut glass.

The impure diamond is used to cut glass due to following reasons -

• As it is the hardest known natural material hence will last long.
• It is cheaper and can produce the required pressure necessary for cutting glass.

Reasons for being diamond the hardest known substance -

• It has a very high intermolecular force of attraction.
• The structure and bonding between carbon atoms are very strong.

Therefore, impure diamond is used to cut glass.