Diamond Buying Guide

The 4C's


From the rarest, colourless D grade, very subtle increases in yellow saturation occur, most people being able to see a softer tint in diamonds at the K colour grade.

D colour is the ‘best’ and of course for an engagement ring sometimes only the best will do. Lower colour grades are not ‘wrong’ they are simply not as rare and therefore cost less. Choosing a less rare colour grade leaves you more money to increase the diamond size or clarity.


Diamonds without any small natural inclusions are extremely rare and therefore the most valuable.

Diamonds in the 'Included' quality range are less rare and less valuable. Precise grading can help you to compare prices, but when mounted in a ring a Flawless diamond and a slightly included one can look very similar. Most inclusions are only visible using a 10x lens, so selecting a slightly included diamond will give you a saving you can put into improved colour or increased diamond size. 


Regardless of colour and clarity, the irresistible fiery brilliance of a diamond is only unlocked by skilled cutting of the diamond rough.

Using a car as an analogy, the cut is the power, the engine performance, a better cut diamond giving superior brilliance and light performance. This can have a dramatic effect on the price of diamonds that are otherwise identical. Book a diamond consultation to see the difference you can’t read on a certificate


The metric weight of a diamond, the term originating in Ancient Egypt where the very uniform sized carob seeds were used as a measure of weight.

A diamond's value increases exponentially with its weight, diamonds being traded in dollars per carat on the world markets. Be aware that the visual size of identical weight diamonds can vary, because a three dimensional diamond can be cut shallow (appears larger) or deeper (appears smaller). Ignore this fact and you could pay for a 0.50 carat weight diamond that has the diameter of a much smaller stone.

Confidence - The Vital Extra C.

Diamonds are small items of extremely high value. Small differences in a diamonds internal features can make a huge difference to the asking price of a diamond.

Similarly, near identical diamonds can have wildly different prices and the reason isn't immediately clear through a shop window. Buying a certificated diamond helps to some degree, but there are some certificates that are wholly inaccurate and diamonds with identical paperwork can appear quite different when seen.  We invite you to visit us and learn about diamonds yourself, first hand, by handling the diamonds you may be interested in buying.

Once you have seen and understood, you will have the confidence to make the right decision about your diamond purchase. To help you understand this further Kayes offer free diamond consultationsYou will be able to learn and see with your own eyes what it is that sets individual diamonds apart.