There is a reason diamonds tend to be expensive – they are rare. Simple enough, right? Okay, they’re also gorgeous, but so are roses, and you can still get those most places for relatively cheap. No, the reason diamonds cost so much, and that so many of us covet them, is that there just aren’t that many in the world.
Now wrap your brain around this: only a small percentage of diamonds as a whole are fancy coloured diamonds. What’s a small percentage of something that’s already rare? Extremely rare. Which is why some jewellers don’t even have a whole lot of knowledge about coloured diamonds.
To make matters worse, the method to rate coloured diamonds is nowhere close to being as clear as that for white diamonds.
The D-Z Scale for White Diamonds, Lots of Words for Coloured Diamonds
Beginning in 1953, the Gemological Institute of America began rating white diamonds on the D-Z scale. Using this, each letter represents how much yellow or brown colouring is mucking up the pristine clarity of the diamonds. The more colour “interfering” with the white, the less valuable the diamond. It’s a simple, clear system that anyone can understand.
Coloured diamonds, on the other hand, have no such clearly defined scale. Unlike with white diamonds, the more red, yellow, blue and so on present in coloured diamonds, the better. But the amount of saturation isn’t conveyed by a letter grade – it’s written out in a description.
Thankfully, the wording of these descriptions has become standardised over time to make it easier to know from a quick read just how saturated a diamond is with a particular colour, but once again, this hasn’t solved the problem.
Why? Because many collectors and enthusiasts simply don’t use the standardised verbiage, preferred to give coloured diamonds ornate names that may sound pretty, but they do little to tell a potential buyer how much colour the diamond actually has or – perhaps more importantly – how much a particular diamond might go for.
Different Colours Valued Differently
But just because “raspberry” doesn’t really tell us how saturated with colour a diamond is, that doesn’t mean it’s a completely useless description. It does tell us that the diamond in question is red, which means that it will likely be very expensive indeed. We can tell this because, quite simply, red diamonds are almost always the most expensive colour, on the opposite end of the spectrum (no pun intended) from less valuable champagne and brown diamonds.
The problem comes in when you start to factor in things like the intensity of the colour. A blue diamond, for example, could typically be expected to be more valuable that a yellow diamond. But if we’re talking about a vivid yellow compared to a standard blue, the yellow might end up costing more.
How Do Diamonds Get Their Colour?
The method by which a diamond obtains a particular hue varies, but almost always it is related to trace elements that can be found within the diamond. Yellow diamonds, for example, get their colour from nitrogen molecules that absorb blue light. In fact, the more gas that a yellow diamond contains, the more yellow it will appear.
Pink diamonds are the one exception to this. While there just haven’t been enough pink diamonds discovered to conduct thorough gemological studies, we do know that their colour is definitely not the result of trace elements. Rather (from what we can tell), the pink hue is created by grain lines that are created when there are disturbances in the diamond’s growth process. These grain lines bend and reflect light, making the diamond look pink.