Diamonds have captivated the imaginations of both women and men for centuries. But there is a marked difference between the intricacies of what diamond traders know about diamond prices and what consumers know about them.

Diamond experts who trade diamonds round the globe daily in the wholesale markets use a set of criteria which has been defined by independent gem laboratories in order to set the price of the diamonds they buy and sell. Without an evaluation of these essential characteristics which determine each diamond’s value, a trade cannot take place.

Professional traders begin by considering the well-known 4Cs before anything else, often before even setting their eyes on the diamond itself. These 4Cs are Carat, Colour, Clarity and Cut. But there is a 5th C which very few people know about. Ehud Arye Laniado was a consummate expert on the measure he calls the 5th C – Comments and other irregularities.

After rigorous examination at a gemological laboratory, each diamond is issued with its own certificate. A diamond certificate lists a diamond’s 4Cs and other crucial information, all of which influence its price. Consumers often overlook the additional information, mostly listed under a section called Comments. But amongst traders it is of enormous importance. Certificates highlight characteristics such as flourescence and the precise position of minute flaws. Quite often, two diamonds with the same 4Cs can differ largely in price due to a host of other factors.

When combined, the 4Cs, the Comments section and further criteria called Irregularities – as explained below - create the basis for systematically valuing diamonds.