The ancient Greeks belived that diamonds were splinters of stars that had fallen to the earth. Some even said that they were the tears of the Gods. Although the diamond is the hardest natural substance known to man, it is also the simplest in composition. It is in fact pure carbon, and has a melting point of approximately 4,000 degrees centigrade. 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. Later the volcanic mass thrust upwards, carrying the diamonds to the earth’s surface to cool in subterranean kimberlite or lamproite known as pipes. It is in these pipes that most diamonds are found today.

Your Guide to Diamond Quality and Value – The 4 C’s

A diamond is judged by four distinct factors that, in combination, determine its value. These are called the 4 C’s – the first letter of cut, colour, clarity and carat weight.


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.

How a diamond handles light

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.


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.


Single DiamondAlmost 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.

There are three major grading systems for classifying diamonds – GIA, HRD, and CIBJO – and an international standard (ISO) is soon to be established. At present a stone is termed flawless by the FIA if it is without surface characteristics or internal inclusions and internally flawless if it has minor surface characteristics. Other systems use the term “Loupe Clean” which equates to both flawless and internally flawless. Grades then gradually descend and are compatible in each grading system.

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.

The Shape of a Diamond

The shape you select is a matter of individual taste. While the round brilliant is the most popular choice, there is a wide variety of alternative shapes.

  • Round Brilliant Cut
  • Oval – The oval is an adaptation of the round brilliant, and appears larger than a round stone of the same carat weight.
  • Marquise – The marquise is the name given to a diamond that is long and pointed at both ends.
  • Heart – The heart is perhaps the most romantic of what are known as the fancy shapes.
  • Emerald – The emerald cut diamond is rectangular, with oblong facets on each side and across the corners.
  • Pear – The pear shape is the English name for the French ‘pendelope’ which is related to our word pendant.
  • Princess – The princess cut creates a bright and scintillating look.

Policy on Conflict Diamonds

Conflict diamonds are those sold in order to fund armed conflict and civil war.
I 2003 the Kimberley Process was launched, making it illegal to trade in conflict diamonds.
In accordance with the Kimberley Process, all diamonds at Forum Jewellers have been purchased from legitimate sources not involved in funding conflict and in compliance with United Nations Resolutions.
The Company of Master Jewellers hold written confirmation from the majority of our suppliers stating their support to and confirming the Kimberley Process. Those suppliers outside of the CMJ all clearly state on their invoices their compliance to the Kimberley Process.
Forum Jewellers therefore guarantees that their diamonds are conflict free, based on personal knowledge and / or written guarantees by the supplier of these diamonds.