What are diamonds made of?

Diamonds are made out of pure, crystallized carbon. Carbon molecules in diamonds are arranged to create a very hard, clear, crystalline structure with a Mohs scale rating of 10. Diamond values tend to fluctuate depending on various grades of transparency and light refraction.

A perfect diamond is colorless and has no flaws or inclusions. However, nearly every diamond has impurities that give it just a bit of color, even if it can't be seen with the naked eye. The same is true of flaws and inclusions.

Graphite and coal are also made of carbon, but the way their molecules are arranged makes them very different substances.