When you are buying loose coloured diamonds or a coloured diamond ring - no matter where you buy it from; at home, abroad on holiday, in a jewellery store, online or direct from a gemstone dealer - you need to make sure you get a Certificate of Authenticity (COA) to go with it. This certificate, also known as a 'diamond grading report', assures you, the buyer, the verification of the quality of your chosen diamond. Basically, this certificate not only gives you piece of mind that what you are buying is genuine, it is your diamond's passport. And since a diamond certificate of authentication is practically the best way of guaranteeing the authenticity of your selected diamond, we highly recommend that you only buy a coloured diamond with this certificate, if the seller does not for whatever reason have one; walk away, walk away, walk away. Plus, many insurance companies now demand to see the COA and may refuse to insure your diamond ring if it doesn't meet the requirements.

Recognised labs like the GIA (Gemological Institute of America) - this is the most well-known but there is also HRD and IGI. These people follow globally recognised diamond standards so no matter where you buy your diamonds from the certificate will show the same results.

What does your certificate tell you?

The certificate has 8 criteria:

• Carat (Weight)
• Clarity
• Colour
• Shape
• Proportions
• Symmetry
• Finish
• Fluorescence

Diamonds are issued with a unique inscription that corresponds with the Certificate of Authenticity. The inscription is made by using a very fine laser onto the girdle of the diamond which can only be seen using a gemological microscope. But even with all this, it will not give you the value of your diamond. Your diamond's worth might be determined by the colour, cut, clarity and weight, but the value of a diamond is also determined by market fluctuations, changes in diamond trends and popularity, etc.

Buy safe, buy happy and you will have a coloured diamond that you can sell in the future, insure in the present and have peace of mind that you know your diamond is exactly what you paid for.