Colour

While most diamonds appear white, many of them display hints of colour.
The closer a diamond approaches to colourless the more exceptional and
more valuable it becomes. Letters are used to denote the colour of a
diamond. The whitest or most colourless diamond is said to be a D colour,
they then progressively become more tinted the further down the alphabet
you go. Each colour grade represents a range of colours, upon reaching an
‘I’ colour, the diamond is said to be slightly tinted white, and may start
to show a slight yellow or brown colour when being viewed in a standard
lighting environment.