Diamond Cut
Diamond Colour Grade
Diamond Clarity
Diamond Carat Weight

Many people have heard of the 4 C’s of diamonds but don’t really understand what they mean and how they impact a purchase decision.

The 4 C’s were developed by the industry’s peak standards body – the Gemological Institute of America – and adopted universally by respected jewellers.

We recommend you seek advice from your Diamond Guild Australia member jeweller to ensure you understand the importance of the 4 C’s and to help you avoid the pitfalls of purchasing a diamond not appropriate to your occasion.

Here’s what you should consider before buying a diamond:


Of all the 4 C’s, cut has the greatest effect on a diamond’s beauty. Two diamonds of the same size, colour and clarity will look vastly different to the eye if cut differently – one may look brilliant and bright, the other dull and drab. The better quality the cut the more brilliance and beauty the diamond will have. Ask your Diamond Guild Australia retailer to show you the difference that an exceptional cut can make to a diamond’s beauty.


A truly colourless diamond is extremely rare. Most diamonds possess varying degrees of colour creating substantial differences in value. The highest grade for a diamond with absolutely no colour is D and letter grades are assigned alphabetically all the way to Z. An ‘icy white’ diamond is typically D, E or F. However, some people like the ‘warmth’ of a I, J or K colour. Within a given budget, you should seek advice from your Diamond Guild Australia retailer on the best balance of clarity, cut and carat to find the perfect diamond for your purchase occasion.


Diamond clarity is symbolic of ‘purity’ – the more flaws, the less valuable the diamond. Flawless, VVS (Very Very Slight), VS (Very slight) and SI1 (Slight Inclusion 1) have the least ‘inclusions’ or flaws. SI2 (Slight inclusion 2) is borderline where inclusions become visible to the naked eye. I (Inclusion) rated diamonds have obvious inclusions or flaws. Your Diamond Guild Australia retailer can offer advice on the best balance of quality and value for your diamond purchase.


Diamond carat is the standard used to measure diamond weight. A carat equals 1/5 of a gram. As diamonds increase in size, their cost tends to increase exponentially. Weight does not always enhance the value of a diamond – particularly if it is cut badly. Indeed a good cut can enhance the perceived size of a diamond. You should consult with an Diamond Guild Australia member regarding the question of carat weight.