Diamonds are a small miracle created in the depths of the earth's core over millennia under huge pressure and heat. They rise from the depths to beguile us. Diamond colour is in fact about the absence of colour. The greater the absence of colour the rarer the stone though most diamonds are born with a hint of hellow or brown.            
Diamond colours are classified by an internationally recognised scale using letters from D down to Z for stones categorised as 'colourless' or 'tinted'.D colour means absolutely colourless, and as you work your way through the alphabet, each letter will show gradually increasing amounts of yellow tint eventually turning more brown than yellow at the letter Z. 
Image courtesy of the GIA.

Most of all, colour affects a diamond’s appearance. 

Put a diamond and light together and the stone will scintillate. When light reflects into the diamond’s facets it sparkles with a range of different hues - what we call 'fire' - refracting the light as it does in a prism.  A noticeable colour in a diamond will prevent light from reflecting or refracting as much as it does in a colourless diamond.

The lower the colour grade the less transparency and scintillation there will be so at Catherine Jones of Cambridge, we commission work using stones top colour stones -  from D to G-colour.

We chose an F-colour oval stone for the centre of our Diamond Trio ring supported for two round brilliant diamonds that are G-colour. 
How diamonds look depends on how clear the crystal is....
Read our next blog about cutting diamonds and how it affects scintillation.