April is the month of diamond, its birthstone. Diamond is also the zodiac stone of Aries. You may have seen our earlier blog posts on the 4 C’s; the main characteristics of a diamond are cut, colour, clarity and carat. In this post we are looking at clarity and carat.

Carat quite simply is the size of diamond. Each significant diamond weight has an optimal width, please see chart below. People are surprised to see that there isn’t much difference between stone sizes. Firstly with any aspect to jewellery it is surprising how much of a difference a fraction of a millimetre can make on the look, impact and design of a piece of jewellery. Secondly, people often forget that carat relates to the diamond as a three dimensional form. When the stone becomes wider it also becomes deeper and this represent the total carat weight of the stone. I mentioned significant sizes with diamonds, in some cases these are ‘magic numbers’. These are diamond sizes where the price suddenly increases I.E at 1.00 carats the price increases dramatically as people like to say they have a carater on their finger, therefore their demand for these on the diamond market is great and the price reflects demand and the rarity. Other magic numbers are 0.50cts, 0.75cts, 1.50cts and you get the picture.

An image to illustrate how the carat weight changes as the millimetre size goes up

Carat Weight chart in relation to millimetres.  Image obtained from http://www.diamondsourceva.com


Clarity is as per the definition; how clear something is. With respect to the diamond are there any marks or imperfections within a stone? Diamonds are pure carbon compacted over a long time under immense heat and pressure to create one of Mother Nature’s beauties… a diamond. Where an area of diamond didn’t have quite the right heat or pressure it can leave imperfections, or a natural finger print some say. Those imperfections or natural characteristics can be miniscule, different colours, in different areas of a diamond and this is how you grade the clarity.


There are many different types of inclusions from a pin point, feather, crystals and each has its own set of characteristics but fundamentally the clarity is assessed on how obvious that marking is. Diamonds in the I range are often referred to as Included or ‘pique’ and they have inclusions visible to the naked eye. SI1 clarity grade and above (small inclusions) needs a 10 x magnification and a trained eye to view the inclusions. The further up the grading scale you go the inclusions become fewer and fewer and more and more discrete. In some occasions due to the way the diamond is cut, the type and placement of an inclusion means that it reflects onto other facets of the stone internally. This effects gives you the look of having far more inclusions than is actually physically in the stone, as this effects the sparkle we avoid using reflectors (we haven’t used one to date). Some inclusions are solely internal whilst others can be surface reaching. When an inclusion is surface reaching further attention needs to be paid to the stone as the jeweller needs to assess if there are any risks to the stone when setting it.

Pictographic to explain how diamond clarity improves up the diamond clarity grading scale

A diamond clarity chart indicating what inclusions you will see within a diamond in relation to their grading.  Image obtained from www.freemandiamonds.com

We keep harking on about trusting your jeweller as it’s really for your own protection. There a lot of decisions made by a jeweller when using it within their jewellery, a diamond is far more than a sparkly lump and some of us don’t get our diamond diplomas for no reason. Trust your jeweller and they should happy and able to answer any questions you may have…. So fire away!

For more info on our bespoke jewellery we have made go to our bespoke page or contact us.

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