The Four “C”s – Carat, Clarity, Colour and Cut

Carat

As with all precious stones the weight of a diamond is described in carats. The word carat originated in a natural unit of weight using the seeds of the carob tree. Diamonds were traditionally weighed against the seeds until the system was standardised and a carat was fixed at 0.2 grams (or one fifth of a gram). One carat is further divided into 100 points. A diamond of 25 points is described as a quarter of a carat. 50 points is equal to half a carat.

Clarity

Almost all diamonds contain tiny imperfections which are traces of the crystal’s genesis. Most can’t be seen with the naked eye and require magnification to be become apparent. Called inclusions, they are nature’s finger print for each and every diamond from its creation. The fewer the inclusions the rarer the stone will be. Clarity is a term that is used to indicate the extent to which the diamond is free of these natural phenomena.

Colour

The majority of diamonds appear to be colourless, others contain increasing tinges of colour (usually yellow) and to a lesser extent, brown. The most valuable of all diamonds are the coloured diamonds which come in blues, pinks, oranges and red. These are arguably the most rare and valuable of all precious stones and the most stunning in brilliance and colour.

Cut (Make)

Of all the four “C’s” the cut is the one most directly influenced by humans. The other three are dictated by nature. The cut or make of a diamond will dramatically influence its fire or sparkle and it is up to the polisher’s skills to release its beauty.A good cut can increase a diamond’s value up to 50% over a poorer cut of similar weight, colour and clarity. It is the cut that enables the diamond to make the best use of light. If a diamond is cut to ‘ideal’ proportions it will have fire as all the light is coming into the stone is then reflected back out at the viewer.The proportions of a brilliant (round) cut diamond have been developed over 100 years to give the diamond its radiance.If a diamond is cut too deep, some light leakage could happen through the opposite side of the pavilion or bottom. If the cut is too shallow, light escapes through the pavilion or bottom before it can be reflected.

Other Aspects Of Your Stone

Proportions

Proportions refer to a polished diamond’s dimensions, facet angles and the relationships between them. For standard round brilliant diamonds, Diamond Grade Reports include the measurements of eight proportions. For fancy shape diamonds (those other than standard round brilliant cuts), Diamond Grade Reports include measured values for the table size and total depth. For all diamonds girdle thickness and culet size are measured with word descriptions based on visual assessment.

Finish

This measures the quality of the diamond’s polish (the overall conditionor smoothness of its surface) and its symmetry (exactness of its outline, shape, placement and alignment of the facets). Polish and symmetry are visually assessed and graded in one of the following categories: Excellent, Very Good, Good, Fair and Poor.

Fluorescence

This refers to the emission of visual light when the stone is subjected to ultraviolet light (or “black light”), emitting a soft bluish colour. It is merely the result of boron molecules being present in the diamond. The more boron impurities are in a diamond the more intense it will fluorese.On Diamond Grade Reports fluorescence is a description, not a grade. The terms for describing the strength of fluorescence are: None, Faint, Medium, Strong and Very Strong. The colour of the fluorescence will also be noted. A description of None, refers to a range of fluorescence from indiscernible to very faint.

Diamond Grade Analysis Reports

These reports will give you all the details of your diamond including cut/make and are prepared using specialist equipment in our Laboratory. We are one of only two independent laboratories in New Zealand with these tools. Diamond Grade Analysis Reports can give you the confidence in choosing a diamond enabling you to compare apples-with-apples. Only then can you make an informed decision when purchasing a diamond.