Choose your diamond

Choosing your Diamond


Giving diamonds as a token of love that dates back centuries. Today is no different, but where should you start? There’s no better place than at Harrington & Hallworth, where every diamond ring is handpicked by our in-store buying teams – often by Mr Harrington himself.


The 4 Cs
There are 4 main characteristics of diamonds that will influence the quality and therefore the price of each stone.


How well a diamond is cut dramatically influences its fire and light. It is the proportions of the cut and the skill of the polisher that determine whether its full beauty will be released. We only select diamonds that have been excellently cut. The shape is a matter of personal taste, with the most popular being the round brilliant. Other shapes are the emerald, pear, marquise, princess, oval and heart.


The closer a diamond is to colourless, the rarer and more valuable the stone. Diamonds with a strong pure colour are extremely rare and can be found in a rainbow of colours from greens and blues through to yellow, red and orange. We sometimes have a small selection of these fancy coloured stones in our showrooms, especially yellow and pink diamonds. The GIA (Gemmological Institute of America) grade colour diamonds from D, which is exceptionally white, through to Z, known as a tinted colour. At Harrington & Hallworth we always have a selection of grade D diamonds in our showrooms.


Almost all diamonds contain small inclusions, or blemishes, many of which are so small they cannot be seen by the naked eye. These are nature's fingerprints and make every diamond unique. The fewer inclusions there are, the rarer and more valuable the diamond. Clarity is the term used to indicate the extent to which a diamond is free of these inclusions under ten times magnification.

  • Flawless (FL)
    No inclusions and no blemishes visible under 10x magnification
  • Internally Flawless (IF)
    No inclusions visible under 10x magnification
  • Very, Very Slightly Included (VVS 1 andVVS 2 )
    Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
  • Very Slightly Included (VS 1 and VS 2 )
    Inclusions are observed with effort under 10x magnification, but can be characterized as minor
  • Slightly Included (SI 1 and SI 2 )
    Inclusions are noticeable under 10x magnification
  • Included (I 1 , I 2 , and I 3 )
    Inclusions are obvious under 10x magnification which may affect transparency and brilliance

To the naked eye, a VS 1 and an SI 2 diamond may look exactly the same, but these diamonds are quite different in terms of overall quality. This is why expert and accurate assessment of diamond clarity is extremely important.


The term carat originates from ancient times when diamonds were weighed against the seeds of the carob tree. Of course the system has long since been standardised, and now one carat is equal to 200mg. Each carat is equal to 100 points, so a diamond of 25 points is described as a quarter of a carat or 0.25ct. The carat weight alone does not determine the value of the diamond. It takes a combination of all the 4 Cs

The 5th C - Certification

Although this 'C' will not affect the quality of a stone it is always worth considering if the diamond you are purchasing will come with a report. This will verify all the qualities of the stone you are buying. Unbiased, scientific reports from companies such as GIA are highly regarded. Although it's not always possible or indeed economical to certify every diamond, the majority of our engagement rings do come with a certificate.