A naturally coloured green diamond is a true rarity of nature. Following red, and ahead of even blue and orange, green is one of the rarest colours in which to find naturally occurring diamonds, and any gem over three or four carats in this hue is an exciting find. Unlike other colours, green is caused by natural irradiation in the earth, probably after the stone's formation. According to Ian Balfour in his book 'Famous Diamonds':
'The green colour is usually caused by the crystal's coming in contact with a radioactive source at some moment during its lifetime and in geological terms, this is measured in millions of years. The most common form of irradiation encountered by diamonds is by the alpha particles which are present in the magma or kimberlite in minute quantities.' Furthermore, the 'intense green' grade given to this diamond is an extremely sought-after title, as is the extraordinary evenness of colour saturation throughout the diamond. More often that not, any hint of green in a diamond is affected by an outer green 'skin' on the stone, which rarely permeates the full crystal, giving such a beautifully even and true colour, as is the case here.