Diamonds

Refers to the number of visible imperfections or ‘inclusions’ in a diamond. These can be tiny fractures or minerals trapped within the stone. When viewed through a ‘loupe’ – the 10x magnifying tool jewellers use to look at diamonds – they may appear like minute clouds, crystals or feathers. The size and position of inclusions in a diamond are important in terms of its value. If they are at the side they may be hidden by the mount and have little effect on the stone’s beauty or brilliance. If they are at the top or in the middle of the diamond however they may impact upon the ability of light to pass through the stone and make it less brilliant and less desirable.

Clarity is graded on a scale from Flawless (FL) to Included (I). The grading is as follows:

FL Flawless - No inclusions or surface blemishes under 10 x magnification

IF Internally Flawless – no inclusions and only insignificant surface blemishes under 10x magnification.

VVS1 – VVS2 Very, Very Small inclusions – extremely difficult to see and usually only visible on a microscope or to an experienced grader with a loupe.

VS1 – VS2 Very Small inclusions, visible with 10x magnification but should still be difficult to find.

SI1 – SI2 Slightly Included, usually easily found with a loupe but still ‘eye clean’, however the inclusions in some SI2 diamonds are visible to the unaided eye.

When viewed without magnification the difference in appearance between 'eye clean' diamonds will be negligible.

I1 - I3 Included - inclusions visible to the naked eye (sometimes referred to as P1 – P3 or piqued). As these inclusions are becoming more visible they may affect the outward appearance of the diamond, the best I1 clarity diamonds may have an inclusion visible to the naked eye of a trained grader but not to the untrained eye and will still be very bright.

Refers to how ‘colourless’ a diamond is. The scale used ranges from the most-coveted colourless D to Z which describes heavily tinted brown/yellow diamonds. Most diamonds sold in the UK will fall within the D-M colour range. Colour differences are extremely subtle and to ensure like-for-like comparisons laboratories use a master set of stones and controlled lighting conditions to avoid ultraviolet light. When we appraise a diamond that is not independently certificated we use GIA certificated diamonds as comparison when establishing the colour.

Refers to the angles and proportions of a diamond and they way in which the diamond cutter has faceted the stone from the original ‘rough’ diamond to release its fire and sparkle. Diamond cutting is an art based on scientific formulas which seek to reflect the maximum amount of light from one ‘facet’ of the diamond to another. Diamonds that are cut too deep or shallow ‘leak’ light from the sides and bottom rather than reflecting through the top of the stone and are thus less brilliant. A well cut diamond of a lower colour and clarity will often ‘outshine’ a better colour and clarity diamond with a poorer cut.

A lesser cut quality is not usually a sign of a lack of skill on the part of the diamond cutter but is usually an economical decision as cutting a diamond poorly can often achieve a far higher yield from a rough diamond than cutting it well. The difference in price between the best and worse cut qualities can be as much as 40% so knowing that a diamond is well cut is vital when comparing stones. Unfortunately even on the best diamond reports the cut grades are somewhat vague and two stones achieving the same cut grade can be very different.

Our diamond buyers are picky about cut quality and will only offer diamonds for sale that they feel are well-proportioned, bright and lively. 

Cut can also refer to the shape of the diamond. The most common is the round brilliant cut diamond, because its shape reflects the optimum amount of light. Other shapes include emerald, pear, marquise, princess and heart.

We stock a wide range of diamond shapes and can explain the pros and cons of each shape.

Refers to the weight of the diamond and makes no reference to its quality. One carat weighs 200 milligrams or a fifth of a gram. A carat can be divided into 100 ‘points’ – which means that a diamond weighing ¾ of a carat can also be termed as being '75 points', a '75 pointer' or '0.75 ct'. As diamonds increase in size the price per carat also increases because larger diamonds are rarer than smaller ones.  Therefore four diamonds with a combined diamond weight of 1.00ct cost substantially less than a single diamond of the same quality weighing 1.00ct. Because diamonds increase in price per carat substantially at certain weights buying just under these weights can be a way of making huge savings or buying a far higher grade diamond.

In recent years, it has become increasingly commonplace for diamonds to be supplied with independent diamond grading reports, also referred to as certificates.  The idea is that it provides some independent paperwork to give consumers additional peace of mind about the quality of the stone they are buying.  Most of our diamonds that are larger than 0.30ct will be supplied with a grading report.  

While most diamond reports or certificates that you will see use the same terminology, the standards to which each laboratory grades can vary and the difference between the most highly regarded reports and lesser reports can in our experience be as much as two grades.  Most of the diamonds we sell are supplied with an independent grading report from the GIA (Gemological Institute of America), although occasionally they may be from HRD (Hoge Raad voor Diamant) or IGI (International Gemmological Institute).  GIA reports are generally the most highly regarded in the industry which is why we tend to opt for them. 

More important perhaps than any of the above you must have confidence in the person that you are buying from, that they are capable of assessing diamonds accurately and are telling you the truth. We have been serving the people of Sheffield for over 40 years. Our customers keep coming back to us and recommending us to their friends because they trust our expertise and enjoy our shopping experience. We hope that you will too.

We have several qualified gemmologists and diamond graders on our staff.  They have completed the Diploma in Gemmology and Diamond Diploma from Gem-A (formerly the Gemmological Association of Great Britain), rigorous and internationally recognised qualifications in gemstone identification and diamond grading.  They will be able to explain diamond grading in as much detail as you need and help you understand the quality of the stones you are looking at.