When you read the literature concerning diamond acquistion, the first thing you learn is that there are “4 C’s” that you need to understand in order to make an informed purchase. Those 4 C’s are Color, Clarity, Carat (weight), and Cut.
For “white” diamonds, the less color the better, with “D” stones considered colorless. Grading is usually done by comparing a diamond to a set of master stones.
Clarity is determined by identifying the number, shape, and positioning of inclusions inside the stone with a 10X magnifying device.
Carat weight is determined with a balance or scale.
Cut is a mathematical/geometrical calculation of the angles of the facets, and what they provide in the way of brightness and dispersion.
All of these factors have an influence on the price of a stone. In fact, though, in many instances, you can’t tell the differences between one stone and another costing 1/2 the price. I’ll give an example using the Clarity of a stone.
The number of inclusions and their placement in the stone affect the clarity grade. There are books available that demonstrate the relative affect a given inclusion will have on the grade. In fact, you could simply read a book on clarity and be able to grade clarity as well as most diamond salespeople. But what’s interesting is that the standard grading is done at 10x magnification. A stone graded at 10X may have 25 times more inclusions if viewed at 15X magnification, and may have no inclusions visible with the naked eye. Inclusions are present no matter what, but the grading is done at 10X.
But the price of a stone may be 50% higher to you, and the extra cost is for something you can’t even see. This happens when you jump from Internally Flawless to VVS, and from VVS to VS clarity grades. In some cases, even when going from a VS to a good SI1. It’s perfectly reasonable to care about the inclusions you can’t see, but often times people would rather put that money toward a bigger stone. Something to keep in mind.