Red Diamonds

Red diamonds are so rare that there is little gemological information about them. What is known is that crystal lattice defects showing stress lamination during the diamond’s formation are the main cause of the red colour.

While there are some diamonds known as “purplish red”, or red with other colour modifiers, a pure red diamond is seldom seen. If you are lucky enough to see a red diamond, you will notice that it does not resemble a ruby, garnet or other red gemstone in colour. The colouring of a red diamond is somewhat sweeter.

In some cases, diamonds that appear red to the eye are actually fancy deep or dark pinks. Although the difference between a moderately dark red, a moderately deep pink and a red diamond is at times subtle, the stone and colour saturation that results in the face-up appearance associated with a red is seldom seen. Every fancy colour diamond, apart from red, has the prefix “intense” or “vivid” in their colour grading scale. Red diamonds, though, are never noted as being “intense” or “vivid” because gemological laboratories consider the red colour itself as “intense” or “vivid”.

The rarity of the gems is reflected in their price. True red diamonds fetch prices of more than seven figures per carat.

Cause of Colour: Similar to pink and brown diamonds, colour in red diamonds is generally thought to be caused by coloured graining, which results from structural irregularities in combination with an impurity. 

Secondary Colours: Red is the colour between purple and orange, so common secondary colours in red diamonds include orangish red, purplish red and brownish red.

Rarity: Pure red diamonds are known to be the rarest of all fancy coloured diamonds, and they command the highest prices. Weighing 5.11 carats the Moussaieff Red Diamond  is the largest graded fancy red diamond in the world.Grading: Red diamonds are graded as

Fancy Red with modifying hues.
Mining: Australia’s Argyle Diamond Mine  produces most of the world’s red diamonds, which are sold at the annual Pink Tender. Red diamonds have also been found in Brazil.