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Diamond is one of the hardest substances that nature produces, which combined with the rarity and beauty of the gem makes it a treasure to be passed through many generations. But not all diamonds are equal, and we assess four major factors when considering a diamond: cut, colour, clarity and carat. All four of these factors impact both appearance and value of a diamond.


The shape of a diamond is important to personal aesthetic but the cut is what fuels a diamonds fire, sparkle and brilliance. Precise workmanship is required to cut a diamonds so its proportions, symmetry and polish maximise its beauty.



A cut grade between excellent and poor is assigned to a diamond based on aspects of symmetry and polish. If a diamond is cut poorly it can appear dark and lifeless, and will appear to lose its sparkle more readily after normal wear. However, a well-cut diamond will return all light and shine brightly regardless of how often it is worn or the way it is set.


Colour grading is also important to value. Naturally occurring impurities within the diamond crystal are the cause of colour in a diamond. Naturally occurring impurities within the diamond crystal are the cause of colour in a diamond. The intensity of the colour is dependent on the concentration of these colour-causing impurities. Diamonds are valued by how little colour is apparent in them, with the exception of fancy colours such as pink and blue diamonds. Our purest white diamonds are graded as D in colour, and the further we move through the alphabet, the more evident the colour becomes.

Colour, apart from the overall shape and size, is the first thing we notice in diamond. At Henderson Bespoke, we recommend investing more in the cut and colour of a diamond, rather than its clarity. Clarity can only be truly observed with the assistance of magnification, whereas colour can be perceived without aid.


Diamond clarity refers to the relative absence of natural occurrences within a diamond crystal. Clarity grades are based on the number, size, relief and position of inclusions and blemishes that can be seen under 10x magnification. Inclusions and blemishes are the natural result of a diamonds formation deep within the earth under extreme heat and pressure. These birthmarks assure us that the gem is of natural origin and diamonds without them are very rare.


Carat is a measure of how much a diamond weighs, with one carat being equal to 0.2 grams. Two diamonds of equal weight can have very different values depending on colour, clarity and cut. 

Coloured Diamonds

Diamonds are generally thought of to be white in colour, but they can be found in an array of hues including pinks, blues, yellows, champagne tones and even black.

Pink diamonds are among the most rare, beautiful and valuable of Earth’s treasures. In the remote north of Western Australia the famed Argyle Diamond mine produced over 90% of the world’s pink diamonds, along with an array of champagne, brown and white diamonds. More than 825 million carats were mined over the life of Argyle however just 0.1% were the elusive pink diamonds amounting to a mere handful over half a carat each year. After three decades the mine closed in November 2020 and these undeniably beautiful and rare diamonds are becoming rarer with each passing day.

Argyle Pink Diamonds ™ are graded in colour according to Argyle’s proprietary grading system which can be viewed here. Essentially, the richer the colour the rarer and more valuable the diamond. Colours range from a light blush (7-9P) to cherry blossom pink (4-6P) to vivid pinks (2-3P) and purplish reds (1PP) with corresponding variation in prices per carat.  Exceptionally rare violet and blue diamonds can also be found. The colours of Argyle are derived from a twist in the crystal lattice structure of the diamond due to the intense heat and pressure on the diamond during formation. This causes light to refract into the recognisable hues of Argyle. This colour derivation is unique to Argyle as colour is often a result of trace elements such as nitrogen in yellow diamonds and boron in blue diamonds. Diamonds actually come in many hues including green which is as a result of natural radiation and even purple which typically indicates concentrations of hydrogen. Black diamonds get their color from large quantities or clouds of minute mineral inclusions such as graphite, pyrite or hematite that extend throughout the stone. 

Enchanting hues can also be found amongst brown diamonds, in particular the champagne tones from Argyle with pink champagne diamonds and golden honey tones coming to life in rose gold settings.

The Gemmological Institute of America (GIA) offers a Coloured Diamond Grading System across six major colour grades being Fancy Light, Fancy, Fancy Dark, Fancy Deep, Fancy Intense, and Fancy Vivid. 

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