Diamond Know How

Buying diamond jewellery can be daunting due to all the terminology and information available on the internet. Ramsdens are here to help and, on this page, we will summarise the key points you need to know when buying a special piece of jewellery.

Diamonds are graded and traded using the principals of the four C’s. This method of grading diamonds was first utilised by the Gemological Institute of America (GIA). Since then, it has become an industry recognised method of grading diamonds which has in turn made the pricing of diamonds worldwide more uniform. By understanding the four C’s you will be able to make an informed decision about the quality of diamond you would like and balance this with your budget. At Ramsdens we have a vast array of new and pre-owned diamond jewellery, giving you a large choice. Contact us today or speak to one of our branch staff to get more help in finding the perfect piece.

The Four Cs


Diamonds are weighed in ‘carats’. There are 100 ‘points’ in one carat, just like 100 pennies in a pound. The carat weight of a diamond usually reflects the diameter of a diamond as most diamonds are cut to exacting proportions to best reflect the light, this is particularly true of round shaped diamonds. The term carat derives from carob seed. Many years ago, before accurate scales, carob seeds were used as a counter weight on scales when weighing gemstones, this worked relatively well because of their uniform size and weight.


The cut grade of a diamond refers to how well the diamond is proportioned. This means how much light and sparkle the diamond reflects, as well as how evenly cut the diamond facets are. This is graded; poor, fair, good, very good and excellent. For a diamond to be well proportioned the pavilion depth and angle, crown depth and angle, table facet diameter and so on all need to complement each other. If one area of the diamond is out of balance with the rest light will leak out and the diamond runs the risk of looking dark and/or dull. This C is the one which is usually forgotten or disregarded but it is hugely important if you want your diamond to look bright and sparkly.


Colour is one of the most important of the four C’s because it can be noticeable to an untrained eye. The GIA grade colour on a scale from D-Z. The colour scale can be broken down into subsections D-F is colourless, G-J Near colourless, K-M Faint, N-R Very Light, S-Z Light. Any diamond displaying more colour than a Z colour, will start to be graded as a fancy coloured diamond. Diamonds are graded facing down so you look through the lower part of the stone. A diamond is colour graded from this angle as it will display the maximum colour the diamond will ever show. The benefit being that when the diamond is viewed from the crown area, less colour is visible. This is important because while a D-F diamond is technically colourless, diamonds graded G-J may well appear colourless when set in a piece of jewellery.


Diamonds formed billions of years ago, between 90 and 140 miles below the earths surface. They are mainly formed of carbon atoms but as the diamond grows it is possible for other minerals to be included in this process. Sometimes a diamonds growth pattern changes and alters course, all these things can lead to clarity characteristics. GIA grade diamond clarity based on the number, position and type of inclusions visible at 10x magnification. The scale includes the following; flawless, internally flawless, very very slightly included 1&2, very slightly included 1&2, slightly included 1&2 and included 1,2&3. Again, it is important to understand clarity grades because it isn’t necessary to have a flawless diamond in order to have a diamond which appears to have no inclusions to the naked eye. Inclusions only start to become eye visible in diamonds with a clarity grade of I1,2&3. Clarity characteristics can be particularly interesting, some diamonds even have ruby or garnet crystals trapped inside them!

By deciding which of these factors are most important to you means you can find the best diamond possible within your budget. For some people the carat weight is most important and therefore they are willing to have a diamond with lower cut, colour and/or clarity to bring the purchase within budget, for others cut, colour or clarity is paramount. Buying diamonds is all about personal choice and balancing the four C’s to our advantage.

In addition to the four C’s the shape of the diamond will be a big decision. You may have a set idea of the shape you would like but it is always worth trying different pieces to see what suits you best. An oval-shape diamond for example may look better on a shorter, wider finger than a round brilliant-cut diamond would as it elongates the appearance of your finger. Some people suit a princess-cut over a more rounded cushion-shape. So, get trying on and experimenting with shape!

How Ramsdens Grading Works

We are happy to provide a Ramsdens diamond grading report for any of our diamonds over 0.30ct. Due to our diamonds being within a setting there are certain limitations to the grading, please see our grading terms and conditions for further information and note that any diamond with a lesser colour than L will be referred to as ‘Tinted’ due to the setting limitations.

This report is issued by Ramsdens Financial Limited (the company) and is subject to the following terms and conditions.

The report is supplied for the benefit of the customer and is issued for their exclusive use. The issuer has made no representation or warranty regarding this report, or gemstone described.

Since gemological classification is not an exact science this report represents only the best professional opinion of the Company.

The Company is in no case responsible for the differences which could occur by repeated expertise and/or other standards, norms, methods or criteria used other than those used by the Company.

Whilst the Company is committed to continually investing in equipment and improving techniques, the results of any other examinations performed on the item may differ depending upon, when how and by whom the item is examined, and upon the changes and improvements in techniques and equipment that may have occurred which may enable the examiner to detect, among other matters, the use of processes for altering the characteristics of an item, or the alteration which became reversible even if the process remains undetectable , which could not previously have been detected by the Company.

The report has been completed based on tests of the item described on the certificate document.

  1. The Company has examined the item(s) carefully with specialised instruments and prepared this report to the best of their knowledge and professional standards.
  2. Expert opinions may reasonably vary as to the characteristics covered in this report, hence the Company or any member of their staff shall not, at any time, be held responsible for any discrepancy which may result from the application of other testing methods. Where gems are set into finished items prior the examination, all assessments and weights given must be considered approximated as the accuracy is limited to the extent that the mounting permits.
  3. The report expresses an opinion at the time of the examination of the item and neither the customer nor any purchaser of the item shall regard this report as an appraisal or as a guarantee or warranty
  4. The liability of the Company for any direct loss or damage which the customer may suffer as a result for this report is limited to the fees paid by the customer to the Company for this report.
  5. The company shall not be liable to the customer for any loss of profit or any indirect or consequential (including economic) loss of any kind which the customer may suffer as a result of or in connection with this report.
  6. This report and any dispute arising out of or in relation to it shall be governed by the laws of England and subject to the exclusive jurisdiction of the English courts.

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