The 4 C
The quality standards that determine the value of a diamond are the 4 C’s: CARAT WEIGHT, COLOUR, CLARITY and CUT. In addition, there is a 5th C for CONFINDENCE, which is not measurable, but just as important.
The measurement for gemstones, 1 carat (ct) is equal with to exactly 0.2 grams. The stone weight determines the price of a diamond. The value of diamonds of equal quality increases over-proportionally with increasing size.
Colour is an important diamond characteristic: the less colour, the higher their value. The expert distinguishes minimal colour shades by comparing them to master stones of established colour grades. Natural coloured diamonds, called “fancy diamonds”, are very rare and therefore especially valuable.
A diamond grading expert evaluates a diamond with his naked eye and a 10x magnifying glass, the more inclusions, the lower the value of the stone. Most diamonds have small natural inclusions. The highest grade, internally flawless, is very rare and valuable. Small inclusions do not reduce the brilliance of a diamond.
A perfect cut gives a diamond its incomparable brilliance. The ideal cut causes the total light to be reflected from the diamond. We call the dispersion of the light into the colours of the spectrum the «fire» of the diamond.