The 4C's of Diamond Buying

About this guide

Very little in life prepares you for buying a diamond, but it doesn't have to be an uncomfortable or overwhelming experience, the 4Cs are here to help!

To navigate the jargon and make sure you get the best deal, we've put together this resource to help guide you through every important aspect of diamond quality, why each aspect matters and how you can get the best for your budget. Each individual guide is written by Simon Porter, Managing Director and owner of James Porter and Son.




Diamond cut defines the shine, finish and appearance of a diamond which heightens its overall shine.



Diamond colour clasifies how 'colourless' a diamond is starting from colourless to obviously yellow.



Diamond clarity identifies internal imperfections within a diamond which affect the overall quality.



Diamond carat refers to the weight measurement of a diamond. Carat has the biggest affect on price.



Often confused with 'cut', diamond contour or 'shape' refers to the form of a diamond once it has been cut.



Some diamonds are certificated by independant labs. Certificates provide details on diamond quality.

Frequently asked questions

What are the 4Cs?

The '4Cs' were first coined by the Gemological Institute of America (GIA). The 4Cs are colour, clarity, carat and cut. These four factors are globally recognised as the main aspects to consider when describing and classifying the quality of a diamond.

Why are there more than 4Cs above?

Although the 4Cs are an extremely useful way of identifying diamond quality, there are other factors involved which you should also know about. Namely diamond certificates and diamond shape. Both have an impact on the appearance of a diamond and it's overall quality so should be included alongside the traditional 4Cs.

Are some Cs more important than others?

The answer for this is yes and no as it entirely depends on the 'C' which is most important to you and the recipient of the diamond. For example, if you think your loved one will be most wowed by overall sparkle then focusing on diamond cut, shape and clarity will be important.

However, if you think size is possible more important, then carat and shape will be more of a focus for you. Each guide above goes into this in more detail.

How can I save the most money?

The number one piece of advice to getting the best deal for your money is to do your research! There are amazing deals to be had if you know what you're looking for. For instance, carat will have the biggest impact on cost.

Getting the best price on carat is in the detail. Buying slightly under common carat sizes such as 0.5 or 1 carat is a great way to save money. Another way is to pay attention to the dimensions of a diamond - some 'carat weight' can be hidden below the setting and never really be seen. Find out more in the guide to diamond carat weight.

I want the best, what should I focus on?

If money is no object and you want to push for the absolute best, focus on the top end of the GIA quality scales. Each 'C' has its own respective scale to classify overall quality.

You can find out how a diamond fares against these quality scales in the detailed certification that comes along with the diamond, read this information carefully. If you’re looking for the very best diamond money can buy, its listed features should include; high carat size, colourless, no visible inclusions, excellent cut into a round brilliant shape.

How can I tell i'm paying the best price for my diamond?

The best way to make sure you're getting the best deal is to do your research and buy diamonds that are certificated. Having a certificate means the diamond has been independently graded and you don't need to take the jewellers word for it. A certificate details every fine detail about your chosen diamond which you can use to discuss with your jeweller.

Need Help?

Contact us by phone at 0141 221 5855 or by email at [email protected]. We love our work and will be happy to help you with your query, we can also book a convenient time for a consultation to find the exactly what you need.

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