A guide for buying a Diamond

The world’s most sought after gemstone is undoubtedly the Diamond. Choosing such a high value entity is a special and rare occasion. Quite like the snowflake, all diamonds are unique. It is easy to perceive the value of day to day goods when shopping for household items or clothes. Considering whether something as delicate as a diamond is worth the price is much more difficult. The value of a diamond is based on several distinct factors and it is the combination of these that result in an end appearance unique to each stone.

The systematic approach to compare, classify and describe Diamonds is often known as the 5C’s.

Feel free to look at each in turn with us:-

1. Colour 

Diamond quality is determined by the absence of colour or deviations from purely colourless, through faintly yellow to traces of brown. An alphabetical scale is used to define the colour saturation of diamonds and ranges from D-Z. D denotes a colourless diamond and Z has very visible amounts of yellow/brown with an obvious detriment to the sparkle and brilliance of the stone.

ADVICE:- Ellisons and Cahoons encourage customers to check their diamonds in natural lighting to see the true colour. Be careful even with certificated stones as steely/greyish and milky/cloudy/hazy hues are common, yet usually disregarded when determining the colour grade. These unfortunate pitfalls can still have a high colour laboratory grading, despite appearing obviously flawed when viewed for real.

2. Clarity

There is no such thing as a perfect diamond. Throughout the many years of its formation, the crystallisation of carbon is never absolute. Hence Inclusions and Blemishes refer to the internal characteristics of the diamond. “Inclusions” are an internal impurity that forms in a precise location where complete crystallisation of the diamond has not occurred. “Blemishes” are surface irregularities that include scratches which may have occurred during mining or cutting of the stone.

Clarity characteristics have a significant impact on the value and quality of a diamond. In theory those stones with fewer inclusions are preferred and have higher values. However no two diamonds are the same and neither is their clarity. Therefore not all clarity factors affect the stone at the same rate. That depends on the nature, size, position and geometry of the flaws. For example, some inclusions are white clouds and so are much more difficult to see than black carbon marks/dots. Likewise diamonds whose flaws are positioned on the sides of the stone tend to have a higher value than those with flaws showing in centre - naturally the latter will be easier to see with the naked eye, thus the stone will be less desirable. 

The Clarity scale that is prevalent internationally consists of 11 grades:-

  • (F) Flawless:- Near perfect | No inclusions visible using 10x magnification | No surface blemished
  • (IF) Internally Flawess:- No inclusions visible using 10x magnification | Slight Blemishes on surface
  • (VVS1) Very-Very Small 1:- Inclusions extremely difficult to detect under 10x magnification
  • (VVS2) Very-Very Small 2:- Inclusions very difficult to detect under 10x magnification
  • (VS1) Very Small 1:- Inclusions difficult to detect under 10x magnification | Impossible to see with the naked eye
  • (VS2) Very Small 2:- Inclusions visible with effort when under 10x magnification | Impossible to see with the naked eye
  • (SI1) Slight Inclusion 1:- Inclusions visible under 10x magnification | May be detectable by an expert with the naked eye
  • (Si2) Slight Inclusion 2:- Inclusions easily visible under 10x magnification | Usually detectable by an expert with the naked eye
  • (I1) Inclusion 1:- Inclusions easily visible to the naked eye
  • (I2) Inclusion 2:- Inclusions are larger and obvious | Little to no brilliance | Fractures
  • (I3) Inclusion 3:- Large Inclusions and imperfections | Fractures and Flaws                                                                                                                                                                                                                                                                                                     

The better the diamond grade, the rarer the stone is. Most of the world’s diamonds are falling in the grades from VS2 to I3. However their rarity increases significantly as the scale rises towards "flawless".

ADVICE:- The size, position and nature of the impurities is very important. The inclusion is much less obvious if coloured white and featherlike when compared to darker crystals. The inclusion can be more easily seen if positioned in the middle (table) of the stone as it could possibly be hidden within the setting if positioned close to the edge or on the side. A blemish that is open to the surface of the diamond can cause structural flaws and this type is much more harmful than those within the stone's surface.

These variations are not necessarily taken into account by a grader, nor described in the grading. The clarity grade simply refers to the proportions of the stone that is included, yet disregards the overall aesthetics of the stone. However they make a hugely significant difference to both the beauty and value of the diamond. Ellisons and Cahoons Jewellers handpick their stones according to their individual aesthetics. This is important when it comes to offering value because a "clearer"/higher graded diamond is not always the more expensive diamond. A diamond with more subtle inclusions on the side might be worth more than a higher graded diamond with fewer, but more obvious inclusions in the centre. This is because the latter would be less desirable, thus lowering the value.  We would encourage you to view each diamond as a separate entity and criticise its physical beauty more so comparing grading reports. You should also only consider buying from reliable sources that you can trust.

3. Cut     

The complexities of the cut are magnified by the way the light reflects off the diamond, revealing the skill and care the craftsman has taken to create a piece of art that dazzles and shines for all to see.

             There are 5 recognised Cut Quality Grades that form the basis of how well a diamond is cut. They are categorised by the presence of Fire (the property of a diamond most easily seen by the naked eye – flashes of colour), Scintillation (the right balance between light and dark areas) and Brightness (how well the diamond reflects light).

  •     Ideal/Excellent:- Premium cut diamonds that have maximum fire and brilliance | Reflect almost all of the light that enters them.
  •     Very Good:- Fine fire and brilliance | Reflect most of the light that enters them | Similar to Ideal diamonds – differences detected only by experts.
  •     Good:- Diamonds that reflect a major proportion of light that enters them
  •     Fair:- Diamonds that lose most of the light that enters them
  •     Poor:- Diamonds that appear dull to the naked eye

ADVICE:- The Cut is often regarded as most important because it determines a diamond’s glitter and dazzle, aspects easily seen by the naked eye. Once again there are pitfalls that can be overlooked by a diamond grader and undetected in certificates. An extra facet can offset the entire symmetry of the diamond. A deep diamond can offer the spread or coverage of a much smaller stone. On the other hand, a shallow or “spready” diamond will leak most of the fire and sparkle, rendering the stone lifeless. If purchased online or without the help of a knowledgeable jeweller, one is usually bound to end up with a diamond that has been sourced solely on price and consequently features some or all of these detrimental features.


4. Carat

The unit used to measure the physical weight of diamonds. One carat is just 0.2g, less than a paperclip! The carat weight is usually determined to two decimal points. For example, a 0.78ct diamond is described as weighing “seventy-eight points”.

Unlike other commodities (e.g. oil, gold), diamonds do not have the same price per unit as their weight increases. For example, a 1.00ct diamond does not cost twice as much as a .50ct diamond of similar quality, but rather the price increases exponentially. Apart from weight, diamonds prices depend on many other variables (colour, cut, clarity). In this way a finer quality diamond can sometimes cost more than a larger, but poorer quality diamond.

ADVICE:- The carat weight of a diamond usually dictates its size and thus refers to the most physical or easily seen property of a diamond. However consumers need to be careful that a diamond has not been cut too thick, just to reach a certain weight as this compromises the fire and brilliance of the diamond. Ellisons and Cahoons Jewellers are careful to properly list all of our carat weights and stock diamonds of an ideal and as close to an ideal spread as possible, whilst still delivering value to their customers.

Some jewellers can use the term “Total Carat Weight”. This denotes the combined weight of all diamonds within the jewellery setting/ring and sounds more impressive. However it is the individual weight of the stones that will influence the price much more than the total carat weight. For example, a 1.00ct 3-stone ring will cost much less than a 1.00ct Solitaire (single stone) ring using Diamonds of the same quality. This is because the larger the individual diamond, the more rare it is and consequently more valuable.

5. Certificated and non-certificated Diamonds

Certificates serve as a blueprint to display the exact dimensions of a diamond in terms of weight, cut and quality. They are not proof of a diamond’s value, yet do verify the qualities that determine its value.

At this point it is necessary to understand that there are no stringent rules on certification and different laboratories can and do have different opinions on the same diamond. Any diamond can be sent to a laboratory for certification. As such this does not mean that it is of superior quality - it cannot change the appearance! Likewise, just because a diamond has not been certified, does not mean it is any less desirable. 

At the bottom of the scale, there are certificates made to look like they are independently owned but are instead subsidiary companies of the wholesaler selling the diamond. Consequently these certificates are basically a sales tool and do not contain a reliable opinion. 

Even more confusing is that there are many independent certificates that are well known in the trade to be unreliable and can exaggerate colour, clarity and cut by up to 3 grades! Most people tend to focus on the certified Colour and Clarity of a diamond, yet there are other characteristics (e.g. cut, symmetry, fluorescence, proportions etc) and it is the combination of all of these factors that dictate the overall appearance of the stone.

At Ellisons and Cahoons, we take our time when choosing diamonds for stock. Each individual stone is closely scrutinised and a decision is made based on its physical aesthetics first and foremost. Secondary to this, is the nature or detail on any associated certificate. Take clarity for example... when comparing two diamonds, one may appear clearer than the other upon viewing. yet this does not always translate on the associated certificate. A Si1 graded stone will in theory contain less inclusions than a Si2, yet this does not take into account the nature or positioning of said inclusions. We would often choose an Si2 over an Si1, if the more numerous inclusions are white feathers and positioned around the edge or pavillion (lower part of the diamond, where it is difficult to see). The Si1 has fewer inclusions, but it only takes one, singular mark in the table (top, flat surface) to be easily detected. Consequently the Si2 in this case would be more desirable and probably cost more than its more highly graded counterpart.

When considering a certified diamond, we would tend to recommend GIA Certification and the vast majority of our certified diamonds reflects this notion significantly. GIA (Gemological Institute of America) are the industry gold standard when it comes to diamond certification. They are world renowned and respected for their strict and consistent guidelines when assessing a diamond. As such the grades are not usually as flattering as their more lenient competitors, however they offer best peace of mind and quality assurance for both us and our customers. 

Buying a diamond with a world renowned and respected certificate can offer peace of mind to the customer and can help in the future if the individual should ever choose to upgrade their stone. However if you are dealing with a reputable jewellers you can trust and have a budget in mind, then a non-certified diamond just might be perfect for you!