Diamond Grading & Quality

There are four main factors which are used to describe and classify diamonds, often described as the 4 Cs (see below) . The 4Cs is the universal grading standard used to determine the value of diamonds. The Cut, Clarity, Colour & Carat of a diamond is determined by a certifying body to grade the diamond.


Of all the 4 Cs, cut has the greatest effect on a diamond's beauty. The cut of a diamond determines how it reflects light. A diamond's reflective properties are referred to as "fire" or "brilliance". A quality cut diamond will have facets angled to reflect the greatest amount of light. This ability to efficiently reflect light requires cutting and polishing the diamond to an extremely high level of accuracy.

The Cut Grading System considers not only the proportions of a diamond, but also the craftsmanship of its overall symmetry and polish. It is unique in that it uses the latest in technology to analyse the cut’s impact on the diamond’s light performance.

Too shallow a cut will let light escape through the sides of the diamond before it has a chance to reflect, making it appear watery or dull, while too deep a cut will allow light to be lost through the bottom of the diamond, making it appear dark, especially in the centre.

Diamonds are cut in many shapes. Some of the more common are; round, oval, pear or teardrop shaped, heart, princess (square shaped), Emerald (rectangular shaped), marquise (oval shaped) and brilliant (round).

Of all the shapes available, brilliant diamonds are the shape most capable of being cut to exude the greatest brilliance, hence the name.

Beware of diamonds cut to maintain a higher carat weight while sacrificing the cutting of a good angle as this will dramatically reduce the brilliance.


A truly colourless diamond is extremely rare. Most diamonds possess varying degrees of yellow or brown and small, subtle differences in colour can make a substantial difference in value. Although increasing shades of yellow can reduce the value of a diamond this does not necessarily reduce its beauty. If a diamond is well cut, the diamond's refraction and dispersion often will disguise certain degrees of colouration. Unless a diamond is a fancy colour (or any colour other than colourless to light yellow or brown), the Diamonds are graded on a 0 to 10 scale, 0 being colourless.

The colour of a diamond is rated on an alphabetical scale from D to Z. A typical 'white' diamond should be as colourless as possible - a rating of 'D' being the rarest and most desirable. When choosing a colourless diamond it is best to stay within the D-J range or the diamond will have a yellow cast which lessens the value. The less natural colour the diamond has the more colours will appear in the flashes reflected in the prism.

'Fancy' diamonds (diamonds with a rating over Z) come in a variety of shades and include some famous diamonds such as the Blue Hope diamond.

Fancy coloured diamonds are diamonds that are naturally coloured when mined such as pink, yellow, brown and black.


The standard used to measure diamond weight is the carat (ct). A carat equals 1/5th of a gram. Each carat is further divided into points, each point representing 1/100th of a carat.

The weight of a diamond is the easiest of the 4Cs to gauge accurately and is the most objective. All that is required is a delicately balanced scale capable of weighting extremely small weights. Yet, despite the ease of measurement and the relative unimportance of diamond weight, there are some facts you should understand about weight and price.

The larger a diamond is the more costly it becomes. Since the larger diamonds are much rarer the cost will go up significantly with each increase in size. A one carat diamond will be more than just double the cost of a half carat, however, a ring with multiple diamonds that have a combined weight of one carat will be cheaper than a single stone of that weight.

First, as diamonds increase in size, their cost tends to increase geometrically rather than arithmetically. Thus, a one-carat diamond may cost more than twice as much as a one-half carat stone of equal quality. Also, as previously stated, weight does not always enhance the value of a diamond. In fact, when a stone is improperly cut, added weight may serve only to reduce its brilliance.

Smalls refers to smaller diamonds, sizing from 0.01ct to 0.30ct and are often used around your main stone as a pavé or channel setting or in our range of men’s / ladies wedding bands and eternity rings.


The clarity of a diamond is the degree to which the diamond contains internal inclusion and external blemishes. The fewer inclusions or blemishes, the more desirable the diamond.

Inclusions are found within the diamond. Two of the most common inclusions are crystals and feathers. Crystals are merely minerals trapped inside the diamond; feathers are breaks in the diamond. Blemishes are usually very small and are only on the surface of diamonds.

The clarity grade of a polished diamond is achieved by inspecting the diamond using 10 x magnifications. This inspection takes into account the size, shape, colour, type and location of the inclusions present in the diamond.