Why are diamonds used to cut glass?

Majority of people knows that diamonds can cut glass. Why is that? This is primarily because diamonds are the hardest materials on our planet and because many diamonds are not suitable for jewelry purposes but are instead used for different other industrial purposes, including also for cutting glass.

However, diamonds aren't the only „stones“ that are capable to cut glass, glass can be for instance also cut with topaz and quartz.

In order to determine which material can cut glass and what can't we need to first know the data of these materials on Moh's scale of hardness. Diamonds as the hardest known substances have hardness set to 10 while glass (used on windows) has the hardness set on 5.5.

What this means is that any material that has a hardness within a range from 5,5 to 10 can be used to cut glass so diamond doesn't have to be necessarily only material used to cut glass.

In order to better understand this you need to learn the definition of hardness. Hardness refers to the resistance of certain mineral to scratching. It is a property by which minerals may be described relative to a standard scale of 10 minerals known as the Mohs scale of hardness.

Diamonds for instance can be scratched only by other diamonds because of their supreme hardness.