Diamonds are the epitome of romantic splendor. The way they play with light - that scintillating way their illumination bounces and twists in our vision- one is never quite able to fully grasp the image of the gem in front of them. The slightest movement, and then, glitter: the view has changed. Inside, broken glass and crushed ice tumble hypnotically amidst celestial fires. Rainbows, hidden in black and white flashes, escape the unseen depths. But this is not the magic of leprechauns; it is the care and work of highly skilled artisans to bring out the extraordinary optical properties inherent in diamonds.
Here we are going to explain a bit about how the anatomy of a diamond works, both rough and cut, to produce these properties.
Diamond crystals are a contiguous tetrahedral composition of carbon atoms. That means that one carbon atom will always be in the center of four others.
See the picture below for an example of how the tetrahedral atomic structure connects carbon atoms to each other:
The element carbon is capable of forming and maintaining some of the strongest bonds that we can measure.
It's a nice reflection, then, that we are also made up of such strong stuff.
But while carbon has unique strength and special abilities, it is the arrangement of the carbon atoms in a diamond that makes it so hard and durable and gives it wondrous illuminating properties. In the image below you can see the macro-molecular structure of interwoven tetrahedral arrangements.
This latticework of atomic structure makes the diamond the hardest material on earth, but technically not the toughest. Hardness is a measure of how much an object may stand up to wear and abrasion. Nothing but a diamond can scratch a diamond. But toughness is how well a material can withstand and absorb forces against it. (Jadeite Jade is the toughest gemstone.) Diamonds are unique because they are stronger in one direction than in another. That makes them slightly brittle and subject to cleavage under the right conditions (which are rarely found outside a cutters workshop, so don't worry about your ring-stone chipping.)
Sometimes another element or object is present that the diamond has to form around, or the forces of its conception arrested for a time before restarting. This is how many inclusions in diamonds form.
In the example of a rough diamond below, you can see the crystal here formed in regular and irregular layers stacked on each other, as if the diamond had changed its mind a number of times about how it wanted to form.