With over 100 years experience and knowledge within these walls, Cox and Son (Goldsmiths) Ltd. is your No. 1 destination for all things Diamond! As diamond specialists, we are fully qualified to advise on the selection and purchase of natural diamonds. With the help of this blog and the 4’Cs- CUT, COLOUR, CLARITY and CARAT WEIGHT, -created by the Gemmological Institute of America, we aim to provide you with enough information to understand the subtle variations that give each stone it’s own unique personality and value. We are confident that you will find your perfect diamond!


Diamonds are renowned for their ability to transmit light and sparkle so immensely. When ideally cut, a diamond has 57 facets are placed in precise symmetrical relation to the others. They act as a series of tiny mirrors, constantly capturing and reflecting light and bouncing it back through the top of the stone in a brilliant blaze.

Cut is often confused with the shape of the diamond. The most common shape, in jewellery, is a Round Brilliant. Although a few others gaining popularity at the moment are; Princess cut, cushion and trillion (triangles). All of the other shapes are known as fancy diamonds. These include Pear, marquise, oval, baguette, heart and emerald cuts.


Diamonds are evaluated and graded on the absence of colour. Most diamonds described as white, are nearly colourless but have a slight tint of colour. Diamonds of a clear white, without colour, are very rare and graded accordingly.

The GIA colour grading scale is the industry’s most widely accepted grading system.

GIA colour grading scale


All natural diamonds will have small inclusions, or known to some as nature’s fingerprints. We can distinguish and grade the diamonds by the degree of perfection visible to the naked eye, or using a 10x loupe (eyeglass). These ‘blemishes’ do not reduce the diamonds brilliance, they are a minor importance and should not affect the enjoyment of the gemstone, although they do substantially lower their cost.

We use the GIA Clarity scale.


The word Carat being adopted from the carob seed- A carat weighing exactly 0.20grams is equal to a typical carob seed.- Typically used as a form of measurement when weighing diamonds.

Although size is significant, it is not the most important factor in determining a diamond’s value, contrary to popular opinion.


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