If a diamond has been independently graded by a gemological laboratory, it is termed a certificated or certified diamond. At A Star Diamonds , virtually all of our diamonds above 0.3ct (and some smaller stones) are supplied with laboratory reports confirming their size and quality.

There are more than twenty organisations around the world that offer these reports. The best known is the Gemological Institute of America (GIA), International Gemological Institute (IGI), and the Diamond High Council (HRD) in Antwerp.

There are minor variations in the way in which these different organisations grade diamonds, but the main focus is on the ‘four Cs’ (carats, color, clarity and cut). Diamond certificates should also tell you whether the diamond exhibits a natural phenomenon called fluorescence.


Avoid Buying Based Only On The Certificate

It is important to be aware that not all the laboratories are equally reliable. If you’d like to learn more of the diamond such as where a certificate has been issued we recommend that clients wherever possible view diamonds in person, so that they can judge the relative beauty of each stone for themselves.


Take for example two diamonds, both graded by the same gemologist as G colour.  One may be on the brim of being an F colour, while the other may be on the brim of being an H colour. A certificate will not tell you this but the two stones will be a discernibly different in colour.

Another gemologist might grade one diamond as VS1 clarity and another as VS2. But the VS1 may be on the brim of being a VS2 and the VS2 on the cusp of being a VS1. The vast majority of people would look at them and see no difference, but the one certified as VS1 might be 10% more expensive than the VS2.

Certificates Of Origin

All of our diamonds can be traced back to mines in Canada and Australia or South Africa, which means that we can guarantee that they are from conflict-free zones.