Diamond Buying Guide What makes us unique

How to buy diamonds

Choosing the perfect engagement ring for your partner can often be tricky – especially as there’s so much pressure to get it right. Our helpful Diamond Buying Guide will give you all the tips and tricks you need to find the perfect centre stone at the best value for money.

The 4Cs

When it comes to buying diamonds, any well-seasoned jeweller will quote the 4Cs to you: cut, clarity, carat and colour. To find a diamond that is cost effective but shines for eternity, it is imperative that your understand the 4Cs.

Cut

Despite common misconceptions, the cut of a diamond does not refer to the shape, but the symmetry, proportion and finish. A diamond cut can significantly affect the brilliance, otherwise known as the light performance, of a diamond. The three things you need to watch out for when it comes to diamond cut are:

• Proportion - a diamond’s dispersive power determines the proportion necessary to maximise its brilliance. Dispersive power refers to the ability of the material to split white light into its component spectral colours – a diamond’s is high at 0.044. If a diamond is too shallow or too deep, the light will not refract within the diamond resulting in a lack of brilliance.
• Symmetry - the brilliance of a diamond is dependent on the facets aligning.I If these facets are not symmetrical, the light will be misdirected as it enters and exits the diamond, reducing the quality of the light performance.
• Finish - the smoothness of a diamond’s facets, or the finish, can affect the brilliance of the diamond. If not polished correctly, a diamond will be dull and lack that desired diamond gleam.

Our top tip: to the untrained eye, it is hard to see the difference between an Excellent and a Very Good cut diamond as the direction of light is the same in both cut gradings. If you are on a budget, the brilliance of a Good cut is often just as strong.

Clarity

The clarity of a diamond refers to the presence of blemishes and inclusions in the stone. These occur when the diamond is made deep underground. Diamond inclusions refer to internal flaws such as air bubbles or internal cracks. Blemishes appear on the outside in the form of as scratches, pits or chips.

There are four major clarity categories:

• Very, Very Slightly Included category (VVS) - separated into two grades – VVS1 denotes a higher clarity grade than VVS2.
• Very Slightly Included category (VS) - separated into two grades – VS1 denotes a higher clarity grade than VS2.
• Slightly Included category (SI) - separated into two grades - SI1 denotes a higher clarity grade than SI2.
• Included category (I) - just one grade, I.

Our Top Tip: infrequently, some VS2 inclusions may be visible - anything slightly included or below is normally visible to the naked eye. We recommend getting a diamond VS1 or above to ensure no blemishes or inclusions are visible. However, in 20% of SI1 diamonds, the clarity issues are not visible to the naked eye.

Carat

Carat is the measurement we use to weigh diamonds – one carat is equal to 200 milligrams, for example, a 5-carat stone will weigh 1 gram. The magic sizes are half carat, three-quarter carat and carat – these are often our most popular weights.

Our Top Tip: 0.01ct rarely makes any difference in appearance but can make all the difference in price. For example, a 0.99ct diamond ring can be noticeably cheaper than a 1ct ring.

Also remember bigger is not always better – while it may seem that a higher carat diamond is preferable, remember your loved one will have to wear the ring on their finger! Carrying around one gram on their finger might be a bit much.

Colour

Confusingly, diamond colour does not refer to colour but rather a lack of it. The colour grades begin at D, with this being the most colourless, and ranges to Z which takes on a more yellow tone.

• Grade D, also known as exceptional white: colourless diamonds are the most desirable since they allow the most refraction of light. 'D' is Pure White - the most valuable colour.
• Grade E, F & G also known as rare white: special whiteness and purity with no tint of colour.
• Grade H also known as good white: brightness with slight tint of colour (usually yellow or brown).

Our Top Tip: Typically, people go for diamonds graded from D to F but G & H can be a good alternative. The untrained eye will not be able to tell the difference between these three ratings.

Ready to buy your diamond ring? Why not visit us in our Hatton Garden store where a member of our friendly sales team will be able to help you choose the perfect ring!