Diamond Buying Guide

The difficulty in buying a diamond is essentially your lack of knowledge on the subject, the high cost of such a purchase and most important, the commitment and symbol of what a diamond purchase represents.

Since you’ve already decided to purchase a diamond and the hardest part is over, I’d like to give you a few tips on how to make your purchase. Before making such a major purchase, however, you should research your options and make an informed decision.

The four Cs

The four Cs are a set of criteria used to determine a diamond’s value and include carat, cut, clarity and colour.


One carat is equal to 0.2 grams, and it is divided into 100 points. However, small weight differences that are undetectable by the naked eye (between 1 carat, or 0.2 grams, and 0.99 of a carat; or between 0.74 and 0.75 of a carat, for example) can make a large difference in value.

Weight is just one of many factors in determining the value of a diamond. The size of a diamond does not necessarily indicate its quality, and a small, high-quality diamond may be worth more than a larger one of lesser quality.


The cut of a diamond refers to its shape and the craftsmanship used to make it. Brilliance, marquise and princess cut are just three options for diamond shapes. The grade and quality of a diamond’s cut are the most important factors in determining its brilliance and fire.


Diamonds formed millions of years ago through pressure and heat, so most contain imperfections or foreign material such as other stones or minerals called inclusions. A diamond’s clarity grade tells you whether the stone contains inclusions or blemishes. There are different grading systems, ranging from flawless (loupe-clear) to a small inclusion visible only under 10x magnification (VS1), right through to those visible to the naked eye (I3 or P3).

The fewer inclusions, the higher the grade and the more valuable a diamond.


Colourless diamonds are rare, while most diamonds have a hint of yellow or brown in them; these are graded from D (exceptional white+) down to Z (tinted, usually yellow). While diamonds that are not ‘pink’ are not extremely valuable, rare pink diamonds (from the Argyle mine in Western Australia) and ‘fancy coloured’ diamonds, like canary yellow, can be very expensive.

Diamonds can be artificially coloured, laser drilled to remove inclusions, or fracture-filled to conceal cracks to improve their appearance. Treated diamonds are viewed as inferior products to natural, untreated stones of similar specifications, and consequently they’re much less valuable.

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