I want a diamond – How do I tell a good one?

Diamond and Sapphire earring

Why are Diamonds so sought after? I think it because they are so beautiful, they sparkle wonderfully, do not wear out and being white in colour can be worn with any outfit. Also there is a mystique surrounding them and a whole raft of specialist knowledge required to tell a good diamond from a bad one. Some diamonds are worth very little and yet others are worth several million pounds.  Here is a brief insight into that specialist knowledge – the things you need to know to tell a great diamond from a poor one.

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Diamonds are evaluated and quantified by the 4 “C’s which together help to determine their value. These are Colour, Clarity, Cut and Carat weight.

Any one of these factory can reduce or increase the diamonds value. The best high value diamonds are large, flawless, and white and cut to show it brilliance to best advantage – it  has high ratings on each of the 4 “C’s”. An un-desirable  low value diamond would be small, yellow have visible flaws and poorly cut – has low ratings on each of the 4 “C’s”.

Most diamonds we see are somewhere in between these two extremes, it requires expert knowledge to determine the exact desirability (value) of a diamond.

Colour:

The colour of a diamond is determined relative to the colour of other diamonds. There are several different scales which can be used to ascertain the colour of a diamond, the best known and the one used here is from the Gemmological Institute of America (GIA).  This scale starts at D (the best white diamonds) and goes through the alphabet to Z for distinctly yellow diamonds. The ones seen in out shops normally range from G to K. The higher up the scale the diamond is the more desirable and more valuable.

Clarity:

Clarity refers to how clear a diamond is, how many internal flaws can be found under 10x magnification. The most desirable diamonds are flawless, these are very rare.

The GIA scale has 7 steps of clarity: – flawless, – very, very slightly included, – very slightly included, -slightly included, – imperfect 1, – imperfect 2, – imperfect 3.

Carat Weight: 

Diamonds are measured in carats, one carat being 0.2 grams. The most accurate way of weighing a diamond is without its setting when it can be put on a balance and measured to the second decimal place. Most of the time diamonds need to be valued when they have been set into jewellery, at this point it is possible to measure a diamonds and then work out its carat weight using complex formulae. There are diamond measuring tools which allow us to estimate the weight of round brilliant cut diamonds but these do not take the depth of the diamond into account,  just the top surface.

Cut:

The cut if a diamond refers to the manner in which the rough stone has been turned into a sparkling gem, it does not refer to its shape. The best cutting brings out the best brilliance and fire in a diamond; it makes the most of its reflectivity. Cutting is a highly skilled process, the cutters aim is to eliminate as many imperfections as possible from the rough stone but to keep the maximum weight.  One of the most delicate parts of the cutting process is faceting, the angles of the facets are crucial for the final appearance of the diamond. If this is done badly they will not reflect the light properly and the diamond lacks brilliance.

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