The number, size, colour and location of any internal inclusions or external blemishes within or on a diamond determines clarity. The stone must be graded under ten times magnification by several qualified graders who will note all the individual characteristics of the diamond and a clarity grade is then awarded.
The colour of a diamond is determined by comparing it with an internationally approved set of master stones. Slight differences in colour can be very subtle but reflect greatly in dollar value. The top three grades (D – E – F) are sometimes known as “Collection” and are the whitest and command higher prices. Once a diamond reaches J/K colour, a slight yellowish tint should be noticeable.
Diamond weight is measured in a unit known as a Carat with each carat being further split into 100 points. A quarter carat may be called a 25 pointer alternatively, a 75 pointer, a three quarter carat. Generally a diamond’s weight is written to two decimal places.
- The Cut or “Make” of the diamond is possibly the most important of the 4 C’s as it can command up to 50% of the diamond’s value
- When grading “make”, critical areas of the diamond are measured using the very latest computer-aided technology. If any one of the areas falls out of a certain set of proportions or tolerances the stone is automatically dropped into a lower category.
- The relationship between various parts of a diamond determines the stone’s ability to return any light that has entered it.
- When cut to Ideal proportions the stone achieves 100% light return or “total internal reflection”, thus the stone will have the maximum brightness and fire, or “life” possible.
- As the diamond proportions move away from the Ideal standard the stone can suffer light “leakage” possibly dulling the stone’s appearance.
- This should be reflected in the dollar value. Simply, an ideally cut diamond will command a higher price than an interior diamond of the same size, colour and clarity because it has better “life”.