Diamonds Demystified

What are they actually made of?

Let’s dig into diamonds, shall we? These sparkling treasures are the ultimate symbol of luxury, often seen shimmering on fingers, dangling from ears, or starring in dramatic movie proposals. But what exactly are diamonds? The single ingredient in a diamond is carbon, with the atomic symbol C - the same element found in graphite and pencil lead. The crucial difference lies in their atomic bonding. Diamonds have covalent bonding, which makes them the hardest substance on Earth.

How do they become the hardest substance on Earth?

It’s all about environmental conditions. You might have heard the saying, "no pressure, no diamonds." This is partly true since diamonds need extreme conditions to form. They develop 90-140 miles deep inside the Earth’s mantle, under extreme pressures of 50 to 70 kilobars and intense heat of 2102-2192°F. They huddle together for millions of years in these conditions, and voilà—a diamond is born and ready for the slow ride to the Earth’s surface.

How do diamonds end up on the Earth’s surface?

Diamond deposits are found in two types of rock: kimberlite and lamproite, which are formed by volcanic explosions. While diamonds don’t form in these rocks, they act as carrier rocks, picking up diamond deposits on their way up and then solidifying on the Earth’s surface. Some diamonds might wait for hundreds of millions of years before they are transported to the Earth’s surface.

So how long did all this take, and how old exactly is my rock?

Unfortunately, diamonds themselves cannot be dated. However, the elements in their inclusions, such as rare metals, can be dated. Researchers have found that even the youngest known diamonds, found in Brazil, are 107 million years old. The oldest diamonds, found in Canada, are about 3.5 billion years old. For comparison, the Earth is 4.6 billion years old! So, if you are carrying a natural diamond on your finger, you can count on it being very, very old. Most diamonds on the market now are between 1 billion and 3.5 billion years old.

How do I know the value of my diamond?

The value of a diamond is determined by the "4 Cs": Carat, Cut, Color, and Clarity, and how these 4 Cs work together.

  • Carat: This refers to the weight of the diamond, with 1 carat equivalent to 0.2 grams. It should not be confused with karat, a unit to measure gold purity.
  • Cut: This aspect dictates how well a diamond reflects light, contributing to its brilliance, fire, and sparkle. A professional diamond cutter considers symmetry, proportions, and polish to maximize the diamond’s optical properties.
  • Color: Diamond color is graded from D (colorless) to Z (light yellow or brown). Generally, the less color a diamond has, the higher its value. However, certain colors like red, orange, and purple are extremely rare and more valuable than colorless diamonds.
  • Clarity: This refers to the presence of inclusions or blemishes within the diamond. Clarity is graded from Flawless to Included. These inclusions make each diamond unique, much like fingerprints or snowflakes.


Diamonds are not just glittering gems; they are ancient marvels of nature. Formed deep within the Earth under extreme conditions and brought to the surface through dramatic volcanic processes, each diamond has a unique history and journey. So, the next time you admire a diamond, remember the incredible natural processes and time span that brought this sparkling masterpiece to you.