Purchasing a diamond is a big decision. So, we want to make sure you’re as informed as possible before taking that leap. We know that not everyone has the time to book a consultation, so here is our diamond guide to give you a breakdown of your options


The Pursuit of the Perfect Diamond

The 4 c’s is the universal method for determining the quality of any diamond. Colour, Cut, Clarity and Carat. Each aspect working hand in hand to give the beautiful stone that you will treasure for a lifetime


The carat is the physical weight of the diamond and is the most apparent feature when comparing diamonds. Where other items are measured in grams, diamonds are measured in carats. To give you an idea, 1carat is 0.2grams. So, the larger the carat size, the larger the diamond.


Diamonds are formed over billions of years, exposed to tremendous heat and pressure in the process. This usually produces slight internal inclusions and external blemishes in the stones. Most of which are so small that experts need to assess the stone under 10x magnification to determine the grade.

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Diamonds comes in a range of tints and colours, from colourless, to yellow, to brown. Colourless diamonds make up less than 1% of all diamonds and are therefore considered more valuable.


What makes a diamond so magical is its intense sparkle and unparalleled shine. That beauty and brilliance is a result of the Cut. A masterfully cut diamond allows light to flow and reflect perfectly, resulting in a stunning display of a diamonds most essential attributes. Brilliance, Fire and Scintillation.

The Different Diamond Shapes


The most popular and iconic diamond shape, known for its versatility and intense sparkle. A round diamond typically has 57 kite shaped facets which allows light to be reflected, The round diamond will never go out of style.

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A contemporary twist on the classic round diamond, with a similar brilliance and sparkle, the oval is a perfect alternative for someone looking for a more slender look

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The perfect balance between the iconic round and the contemporary princess cut, the cushion diamond is square with soft rounded corners, giving it a art-deco appearance.

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A modern and contemporary look, the princess diamond has shot up in popularity due to its brilliant cut and pyramidal shape, giving it an intense sparkle.

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The pear diamond, also known as the teardrop diamond, is an artful mix of the sleek marquise shape and the iconic round.

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The most clear and transparent of all the diamond shapes, the pavilion of this diamond has rectangular facets, displaying the clarity of the diamond in a glass like fashion. Perfect for someone looking for an elegant style, without the intense sparkle.

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Originally commissioned by Louis XIV, the marquise diamond gives the most slender appearance out of all diamond shapes, whilst still maximising the carat weight. Perfect for delicate hands.

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Also known as the square version of an Emerald cut. The Pavilion is cut into rectangular facets displaying the clarity of the diamond in a stunning way. Perfect for a glass-like look in a contemporary shape.

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One of the most uncommon cuts, the radiant diamond has the most brilliance of all square shaped diamonds. This with its versatile shape make it a great choice for any ring style.

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The most unique and romantic diamond shape out there, made from a modified round diamond the heart shape diamond keeps the brilliant sparkle of a round diamond, with an added romantic twist

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Diamond FAQ

Ring resizing is free to all clients who have created the ring with JCO London, as part of our lifetime care provided by us.

The fewer sizes the ring is resized to, the better. Typically, rings can be altered up or down by 3 ring sizes. Any more than this, and the ring would have to be entirely remade.

No, but there is a limit to how many times you should resize your ring. If possible, try to stick to less than three resizes throughout the ring’s lifetime. If a ring is resized any more than this, it is likely to become weaker and less durable to withstand life’s daily activities. If you’re looking to resize an antique ring, consult an expert to ensure the ring is sturdy enough to withstand alterations.

Resizing your ring isn’t always the best option - and in such instances adding what we call ‘speed bumps’ may do the trick. These small additions (to the inside of the band of the ring) can help to create a more comfortable fit that ensures your ring won’t twist around.

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