Free shipping to Mainland UK when you spend over £45 on Forum Jewellers

Our guide to diamond quality with the 4 C’s

Billions of years ago, the elemental forces of heat and pressure in the cauldron of boiling magma that lay deep below the surface of the earth miraculously transformed carbon into diamond.

Cut

Of all the 4C’s, cut is the factor most directly influenced by man, the other three being dictated entirely by nature. The cut or make of a diamond will dramatically influence its fire, brilliance and sparkle, so it is the polisher’s skill that determines whether its full beauty is released.

It is the cut that enables a diamond to make the best use of light. When a diamond is cut to good proportions, light is reflected and refracted from one facet to another and then dispersed through the crown or top of the stone. If the cut of the diamond is too deep or too shallow, some light escapes through the pavilion or bottom before it can be reflected.

Colour

The colour of diamonds can vary appreciably, ranging from totally colourless through to a yellow, grey or brown hue. Rare fancy-coloured diamonds are also found, and include blues, pinks, oranges, greens, yellows and browns.

Clarity

Almost all diamonds contain extremely small inclusions. Most are not discernible to the naked eye and require magnification to become apparent. They are nature’s fingerprints and make every diamond quite unique. The fewer there are, the rarer and more valuable the stone.
Clarity is the term used to indicate the extent to which the diamond you purchase is free of these natural inclusions under ten times magnification.

CARAT WEIGHT

As with all precious stones, the weight of a diamond is expressed in carats. The word carat originates from a naturally occuring unit of weight – the seed of the carob tree. Diamonds were traditionally weighed against these seeds until the system was standardised, and one carat was fixed at 0.2 grams (one fifth of a gram).
One carat is divided into 100 “Points” so that a diamond of 25 points is described as quarter of a carat, or 0.25 carats.