In an interesting LinkedIn Pulse post, Gideon Golan explains how differences in atoms and structural models or exposure to outer radiation during their formation are the reason why some diamonds are coloured while others are “white”, or more precisely more or less “transparent”. Strangely enough, what creates today’s most sought-after and high-priced fancy coloured diamonds are called “defects”. Exposure to the right amount of radiation can create fancy deep green diamonds, while certain amounts of nitrogen in the atomic structure of diamonds result in the illustrious canary yellow or orange diamonds. Only a few “parts per million” (PPM) of boron atoms on the other hand create the most wondrous blue diamonds. Brown, purple, pink and red diamonds are caused by so-called “vacancies”, or otherwise put, the absence of certain molecules.
However, the most important aspect that determines whether a colored diamond becomes a true treasure is the craftsmanship of the manufacturer, Gideon concludes. “It is the work of the manufacturer to decide how to best bring out the color with regard to cutting the stone at the right angles and proportions, also the right shape for fancy color, to make those "defects" shine out and increase the value of this even more rare diamond.”