Blue Diamond
In their purest form, diamonds are colorless. Colorless means that the stone itself does not absorb any light, but reflects all of it back to the observer, causing him to see white light, or what the human eye interprets as colorless. Blue diamonds are actually diamonds that absorb all wavelengths of light except for blue. What makes a blue diamond absorb light are impurities in its molecular structure. In the specific case of a blue diamond, that impurity is an element known as boron.
Whereas carbon, the main element of diamond, has a quadruple bond capacity, boron can only make three bonds. Therefore, when a boron atom is stuck in the middle of a lattice of carbon atoms in a blue diamond, one carbon bond is left loose, giving light a little bit of an obstacle course bouncing around a floating orbital and out of the stone. The angles the light bounces, thanks to the structure of the carbon-boron bond, make it that the only light able to be reflected off the stone is blue, creating a blue diamond. The more boron impurities in a diamond lattice, the more intensely colored the blue diamondis.
Only .01 percent of all natural diamonds mined on Earth are colored. This makes sense, in light of the fact that boron is only present in .0001 percent of the earth’s crust. This gives a hundredfold disparity between colored diamonds in general andblue diamonds in particular. This is because there are many other impurities that can yield other colors in diamonds. Blue diamonds have to be in the exact right place at the exact right time to form with enough boron in their lattice to form the blue color that makes them so valuable. All it takes is 1 boron per every million carbon atoms to do the trick.
The most famous of the blue diamonds above the earth’s crust today is the Hope Diamond. Just as with any stone that has traversed history, nobody knows where the blue diamond came from, but people speculate India. This blue diamond was passed around for centuries, ended up with Louis XIV, the Sun King who reigned for over 70 years in pre-revolution France, and was then stolen from the French royal treasury, recut, and the blue diamond somehow ended up in Washington D.C.
As for the element responsible for the blue in blue diamonds, boron continues to get the short end of the deal. But, as the cartoon Futurama often used to advertise in its heyday, “Nobody Doesn’t Like Molten Boron!”
