• The Four C's

All diamonds used by Lewis Malka London have been purchased from legitimate sources not involved in funding conflict and in compliance with UN resolutions. Our diamond sources guarantee that all diamonds supplied are conflict free, based on personal knowledge and/or written guarantees provided by the suppliers of these diamonds.

Before you begin shopping for diamonds, you need to learn and understand them. I've put together a basic guide to help with the fundamentals. Understanding diamonds is really all about understanding and getting a good comprehension of the 'Four Cs' of diamonds - Cut, Clarity, Colour and Carat weight. These are the basics jewellers use when grading diamonds and trying to determine their value. They are also the ones you'll need to understand to find the right diamond for you. Further information can be found at the GIA website. Click on the guide at the bottom of the page to find out more.




In my opinion the cut is probably the most crucial of the 'Four Cs' to understand. The brilliance of a diamond depends heavily on its cut. Here at Lewis Malka London I make sure we use only the better grades of diamond cut. This would be either classed as excellent or very good. This is to guarantee that your jewellery is as beautiful and sparkly as possible. My guide shows you how to choose a diamond with the best cut. You don't want a stone that's either to shallow or to deep. You need to ensure the proportions are well balanced thus getting maximum refraction from your diamond.

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All diamonds will have some sort of inclusion within, it's all part of the process that the carbon undergoes during those many years of pressure and high temperatures. The visibility, number and size of these inclusions establish the clarity of a diamond. Diamonds that are clear create more brilliance. The clearer the diamond, the rarer the diamond and the more expensive it is. I would say that most people will have inclusions in their diamond, however it's the size of the inclusions which matter. I believe a diamond which is graded as "vs" shouldn't have any illusions which the naked eye can see. I recommend either a VS2 or SI1 as a starting point for a good "eye clean" clarity.

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I highly recommend that when picking a colour for your ring, to go for a colour grade between D and G. Colourless diamonds are traditionally considered the most desirable. They allow the most refraction of light (sparkle). Off white diamonds absorb light, inhibiting brilliance. It's so subjective though and the truth is you won't see the difference once you have your ring as you will never have two stones next to each other to always compare with. Yes, there will be a big difference between price from one end of the scale to the other, but what you spend on the colour you can loose on the clarity or carat if you are working to a budget. If you can't see the difference your friends won't either.

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Carat Weight

A carat is the unit of weight by which a diamond is measured. This came about from the Egyptians many years ago. They used to have a carob tree which produced the carob seed. It's said that all the seeds were an identical size and weight so this became the benchmark to be measured against. Over time, carob became carat. The pricing of a diamond is based on a curve upward chart. The bigger the stone, the rarer it is, the more expensive per carat the diamond is. The same stone visually can be considerably cheaper if you went for the smaller version of it. For example if I want to buy a 1.00ct diamond which has a spread of 6.4mm but it was a bit out of my price bracket, I may want to opt for a 0.95ct stone instead. This can save me hundreds of pounds yet still look the same as a 1.00ct stone. Remember it's the weight of the diamond not the diameter that makes it a 1.00ct diamond.

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The diamond certificate, which is sometimes called a grading report, is a complete evaluation of your diamond that has been performed by a qualified professional with the help of special gemmological instruments. Each stone bears its own recognizable, individual characteristics, which are listed on the certificate.


The Gemological Institute of America, or GIA, is a non-profit institute dedicated to research and education in the field of gemology. The GIA is also well known for its gem identification and grading services, and developed the famous 'Four Cs' (Cut, Clarity, Color and Carat weight) methodology of grading diamonds. Although the GIA is best known for its activities in relation to diamonds, the institute is also involved with colored gemstones and pearls. The GIA was founded in 1931 by Robert Shipley in Los Angeles, California. Today, the institute is headquartered in Carlsbad, California, north of San Diego. Lewis Malka London uses mostly diamonds which haves been graded by the GIA.

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