Diamonds: How They Form

September 10, 2015
Stewart Kuper

Nearly everyone on Earth can identify a diamond on sight. Their look is unmistakable. Their rarity is phenomenal. Their value, undeniable. Their beauty, seductive. So where do these incredible and unique stones come from? How are they formed, and why are they so very rare?
What are Diamonds?
Well, technically speaking, diamonds are a metastable allotrope of carbon. That sounds incredibly complicated, but the important thing to get out of that phrase, is that diamonds are made out of carbon. Do you know what else is made of out carbon? You are! Human beings are carbon based lifeforms. In fact, every living organism on Earth is a carbon based lifeform. We are all made largely of the same material as diamonds. The thing that sets a diamond apart, is the shape the carbon takes.
How They Form
Diamonds form deep inside the Earth’s mantle. It takes incredible pressure and heat to form a diamond. The formation of diamonds does not begin until 87 miles below the surface of the Earth! The creation of a diamond also takes time, 1 billion to 3.3 billion years to be exact. That means that there are diamonds that are almost as old as the Earth is itself! The extraordinary circumstances that lead to the creation of diamonds also lend to their extraordinary characteristics. Diamonds are the hardest know natural occurring material in the world, and because of this, they are also one of the sharpest. Beyond their use in jewelry, diamonds also have vast practical and commercial applications.
Possible Impurities
Because diamonds are so incredibly strong, and form under such immense pressure, they can be contaminated by very few impurities. Nitrogen and boron are two of the only materials that can mar the perfection of a diamond. The result of these imperfections can be surprising! Boron imperfections can cause a diamond to appear blue, while nitrogen can cause it to appear yellow!