The Guide to Diamond Certificates
What is a diamond certificate?
When a diamond has been certificated it means it has been examined by an independent gemological laboratory who provide an unbiased and expert assessment of the quality and grading (the 4Cs) of a diamond. Some jewellers will provide their own in-house 'certificate', but this is not recognised as an industry standard in the same way an independent certificate is.
A diamond certificate will provide you with every important detail about a diamond, from the cut, colour, clarity and carat weight, to the proportions, polish and symmetry. You will also commonly find a sketch of the diamond to illustrate the inclusions in the stone and a unique identification number which belongs only to that diamond.
All of the major diamond certification laboratories have an online checking system which you can search using the ID number so you can research with complete peace of mind when making your purchase. A diamond certificate is usually referred to as the 5th 'C' when it comes to diamond buying and provides complete transparency when buying a stone.
What are the best certificates?
Certificates are a good thing to look for when purchasing a diamond, but be aware as not all certificates are created equal and some are more detailed than others. Below are three of the top gemmological laboratories worldwide who provide the most detailed and highest quality diamond reports:
How to read a diamond certificate
When you know what to look for, a diamond certificate can be pretty easy to read, but if you haven't seen one before - which will be the case for most people it can be a bewildering.
To give you an example, we have found a sample report from the GIA. Each certificate regardless of origin, will have the table of all the possible grades for each of the C's which are the most important gradings to review when making your decision.
You can find out more about the 4Cs in our guide. You will also find that any jewellery consultant in a store will be able to explain the details to you. Below we have highlighted these most important parts but generally speaking, reports are self explanatory:
Frequently asked questions
Is Certificated better than non-certificated?
When coming to choose a diamond, certification provides reassurance in what you are buying is verified in its overall quality. However, as i'm sure you can imagine, certification comes with an additional cost.
A certificated diamond will come in at a premium when compared to a diamond the same quality but without a certificate. The cost of certification depends on the laboratory used and the size of the diamond but, you should expect to pay between £100-£300 for most stones.
What if a diamond doesn't have a certificate?
As long as you buy from a reputable jewellers they should be able to provide you with the information you need on your diamond purchase. Most jewellers will even provide you with some diamond grades if you ask them so you can have the information without the additional cost of a certificate.
I'm buying a certified diamond but i've not heard of the lab before
If you are going for a certificated diamond, be sure to check the credentials of the certificating company. Some are more highly regarded than others, so do your research or try and stick to the more well known ones if possible.
Is there really a benefit to getting a certificate?
Having a certificate is like a security blanket for your purchase, it means your diamond is independently graded and you don't need to take the jewellery consultants word for it. You will also find your certificate beneficial if you were to ever sell your jewellery or pass it down through your family.