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Diamond Guide


Our informative diamond guide will tell you everything you need to know about diamonds. From colour to clarity, we have all the need to know information so you know exactly what you are receiving when purchasing diamond jewellery.

Diamond Colour Scale

The colour of your diamond is determined on a scale from Z to D. The less colour a diamond has, the higher the quality. A colourless diamond is rated D, while a diamond saturated in colour is rated a Z. Diamonds with some colour are rated between E and J, depending on how much colour is present.

D - Absolutely colourless, the highest colour grade and extremely rare.

E/F -Colourless and a rare, small traces of colour can be detected by an expert gemmologist.

G/H - Almost colourless, often difficult to detect unless compared to better grade diamonds of better grades.

I/J - Near colourless and good value with slightly detectable warmth or tone.

K/Z - Noticeable saturation.

Diamond Clarity Guide

Clarity refers to how many imperfections a diamond has. A diamond with little to no visible imperfections is rated flawless, while a diamond with a lot of imperfections are rated I1. A flawless diamond is very rare and so very expensive, while a I1 diamond is a lot more common and cheaper in price. Most imperfections are not visible to the naked eye and are only spotted through professional magnification.

FL - Flawless with no visible blemishes

IF - Internally flawless with very slight blemishes

VVS1, VVS2 - Very, very slightly included

VVS1 - Few miniscule inclusions

VVS2 - Slightly more miniscule inclusions

VS1, VS2 - Very slightly included. Minor inclusions ranging from difficult to somewhat easy to see.

SI1, SI2 - Slightly included.

SI1 - Has inclusions and are occasionally visible to the keen eye without magnification

SI2 - Inclusions are typically visible from the pavilion, and often seen from the top without magnification

I1 - Included

Diamond Shapes

The shape of the diamond should not be confused with the cut. The cut relates to the diamond’s proportions and facets, while the shape refers to the overall appearance of the diamond.


The round brilliant cut diamond is the most popular. A round diamond will give you more flexibility when selecting the cut, colour and clarity grades to obtain optimum fire and brilliance for your budget. You may have heard of a term called “Ideal Cut”. This term refers to the attempt to cut a round diamond into the best proportions to achieve maximum brilliance, fire and scintillation.


The beautiful brilliance and unique cut makes it a favourite for engagement rings. The princess has pointed corners and is traditionally square in shape. It is effectively a square version of the round brilliant cut. The extra faceting results in far more sparkle than previously seen in the ordinary square cut diamond.


Cushion shape diamonds (also known as "pillow-cut") have rounded corners and larger facets to increase their brilliance. These larger facets highlight the diamond's clarity therefore you should always go with a high clarity grade.


A Marquise or Navette diamond offers a slim oval design, similar to a boat shape. A Marquise diamond usually features 58 facets with 33 on the crown and 25 on the pavilion, though the pavilion facets can range from 4 to 8. This particular shape is sometimes cut with a French tip in place of the large bezel facet.


Due to the larger, open table shape highlights the clarity of a diamond. Therefore always choose a high clarity grade. Also, emerald-cut diamonds can vary greatly in how rectangular they are. If you'd prefer an emerald cut with a squared outline, look for an Asscher-cut diamond, which has the same type of cut.


Trimmed corners are the signature of this diamond, and they help make the radiant-cut a popular and versatile choice. The radiant cut is often confused with a “cut corners princess”. The cut corners are distinguishing of this fancy-shaped diamond and they aid in the brilliance of the diamond.


The pear shape cut combines the round and marquise cuts as another variation of the brilliant cut.


An oval diamond has beautiful brilliance (sparkle) that's very similar to a round diamond. Oval diamonds can accentuate long, slender fingers.


The Asscher cut diamond is nearly identical to the emerald cut diamond and is often referred to as a square emerald cut. because of its high crown and small table, the Asscher cut diamond has more light and fire than an emerald cut diamond.


The heart is the ultimate symbol of love. The unique look of the heart-shaped diamond makes it a distinctive choice for a variety of diamond jewellery. When choosing a colour grade, consider that colour may be slightly visible in its corners.


The trilliant cut is one of the more unusual diamond cuts, displaying a very sharp brilliance. This is a lovely style of cut for shoulder diamonds to enhance a square or rectangular shaped centre diamond.


The Baguette Cut Diamond is usually cut with straight sides and four sharp corners. The pavilion facets are step-cut which can give the overall appearance a very striking appeal. These diamonds are usually used as shoulder stones to enhance a larger centre stone and usually found in only smaller sizes.

Diamond Carats

The carat measures the weight of a diamond, not the size. The higher the carat, the heavier the diamond. Larger diamonds are very rare and precious and their high prices reflect this. Carats are separated into points. 100 points is the same as 1 carat. For example:

Half a Carat = 50 Points or 0.50 Carats

A Quarter Of A Carat = 25 points or 0.25 Carats

If there is more than one diamond on a piece of jewellery, all diamonds are weighed together and add up to the overall carat of the jewellery item. At Joshua James, we feature a range of diamond jewellery for you to choose from. Browse our collections of charms, bracelets, necklaces, earrings and rings for simply stunning diamond jewellery from top designer brands.