Diamond Trust

So, everyone gets told about “The 4Cs” (colour, clarity, carat weight, cut) and that they all play a factor the price of the diamond, but the cut in my opinion is the biggest factor in the value of the diamond.  So let’s break it down: colour and clarity, aside from treated stones, are two facets of diamond grades that are completely out of the hands of the miners, diamond cutters, wholesalers, diamond certification organisations and retailers.  The rough gets dug out of the ground, and nothing we do is going to change the colour and clarity.

The carat weight is also partially determined by what comes out of the ground, but the type of cut determines how much of that rough carat weight sticks around for the finished product. To give you an idea, a modern round brilliant cut might lose 70% of it’s carat weight and a princess cut around 60%.  There’s no exact amount that it will lose and due to the irregularity of the shape of the rough it will always slightly vary, but that gives the cutter a clear choice: cut for weight or cut for proportions (or what you refer to as the “cut” in the 4Cs).

I’ll give you an example, they might have an F/VS1 stone and they could aim to have a cut and polished weight of 1.00ct with fair proportions or 0.98ct with excellent proportions.  What’s the incentive to go for fair proportions?  Well, at time of publishing, a round brilliant cut just under 1ct vs. one just over 1ct is approximately 45% more expensive per carat.  But, to be fair, the seller will probably (hopefully!) not pass the full price increase onto you if the larger one doesn’t have the same cut grade.

So, it would seem that around the boundaries of pricing brackets that cut and carat weight can be inversely correlated and I’ll finish this post with a question: would you rather have a poorly cut and marginally larger stone that you paid up to 45% more for, or a 0.98ct stone which came from the same rough and is brilliant?  I know which diamond I’d have bought!