Coloured Diamonds
Learn all about natural fancy coloured diamonds through the Raliegh Goss fine jewellery brand.
There are many different natural causes in the formation of coloured diamonds that give them their specific colours. Boron, hydrogen, nitrogen, distortions to the diamond's crystal lattice due to pressure, or exposure to radiation all effect the coloration in the formation if the diamond. There have been 300 colours identified so far. Only one natural colour diamond in every 10,000 colourless diamond, will make an appearance from the earths core.
Like the colourless diamond, they too are graded by the 4 C’s, however it’s colour grading is far more complex. There are close to nine colours that are prominent within natural fancy coloured diamonds < brown, yellow, white, grey, pink, blue, orange, green, purple, and red. Red being the rarest of the colours. There have only been around five “red” colours found in the world. Diamonds that have been exposed to radiation will most likely have a green colour.
These colours will more often have other hues, for example; A natural fancy “greenish yellow” is a yellow diamond that has green hues. Whereas a “yellowish green” is a green diamond with yellow hues.
Coloured diamonds are graded by their hues and saturations. The least variation of hues a colour has the more expensive they tend to be. A straight natural fancy coloured yellow diamond is more expensive than let’s say a natural fancy coloured “brownish yellow” diamond. The saturation is fairly obvious in terms of its value, the deeper and stronger the colour, the more expensive they are. The saturations go as follows; faint, light, fancy, intense, vivid & deep.
Within the industry we use the term 'Natural' & ‘Fancy’ before ‘coloured diamond’ this is because often colour enhanced diamonds are easily available and advertised as ‘coloured diamonds’ but these are nowhere near as valuable.
In fact around 80,000 carats of rough diamonds that are mined every year, only 0.001% turn out to be fancy coloured diamonds.
Blue Diamonds
Yellow Diamonds
The blue diamond adopts its luxurious colour at an early stage. The more boron, the more intense the colour. Very occasionally due to the presence of hydrogen, a greyish blue appears. Blue diamond’s generally come from South Africa, while a small number of deep blue
diamonds are found in Central Africa, Brazil & Borneo.
Historically, blue diamonds have been found in India
and metallic blue diamonds have been found in the
Argyle mines in Australia. In November 2014, a
9.75 carat blue diamond, the Mellon Blue, sold
for a staggering $32.6 million at Sotheby’s
in New York, before being renamed
the Zoe Diamond.
Pink Diamonds
Brown Diamonds
Fiery yellow coloured diamonds are created thanks to the presence of nitrogen. Yellow diamonds have become more appealing to the end consumer in the retail world due to their appeal in value, as far as
coloured diamonds go their prices are more attainable than
the pinks and blues. There are unconventional diamonds
of character in the yellow hues such as “lime”
diamonds that are classified as natural fancy
greenish yellow diamonds. Yellow diamonds
are mostly mined from Brazil, Russia,
Australia and Africa. The more intense
colours are typically found in South Africa.
A pink diamond is formed under astounding
pressure under the earth’s surface when its crystal
lattice deforms. Fancy coloured diamonds including
pinks, generate even higher returns than colourless diamonds,
Rare pink diamond prices have increased by 443 percent in the
last 10 years and in some cases, can reach 50 times the price of a
colourless diamond equivalent. The largest mine for pink diamonds
is the Australian Argyle mine, although smaller quantities are also mined
in Borneo, Guinea, Brazil, Angola and South Africa.
Orange and brown diamonds, often called cognac,
champagne and even cinnamon diamonds, are formed
by the presence of nitrogen. A pure orange colour is the
rarest colour of this category and is caused by a combination
of nitrogen atoms and structural deformities. Brown tone
diamonds are mined in Australia, Borneo, Brazil, the African
continent and Russia. Orange diamonds are found in South Africa, the Democratic Republic of Congo and Russia.
White diamonds are classified as fancy coloured diamonds. They are often opaque and have an opalescent milky effect, unlike the natural causes of colouration in other fancy coloured diamonds, white diamonds contain a high concentration of sub microscopic inclusions that scatter light. Although unknown, it is believed that it is the presence of nitrogen that causes these inclusions in the diamond’s carbon structure. Colourless diamonds outnumber coloured diamonds by 10,000 to 1 and white diamonds in particular are extremely hard to come by.
Natural Fancy White Diamonds
Chameleon Diamonds
We call these diamonds “Chameleon” because much like the reptile, they are able to change colour. Chameleon diamonds were only first recorded around 1943, with only few people being aware of their magical feature to change colour.
These diamonds became more valuable once people started to acknowledge their scarcity and their unique abilities.
It is when a chameleon diamond is viewed under different temperature and light conditions that they change their colour. Changes in heat of about 250 degrees Celsius will make the diamonds temporarily turn green to olive or yellow. Naturally, the larger the diamond, the more evident the change in colour.
It is the only registered diamond to have this unusual characteristic, one can determine this by having the diamond certified by gemmological laboratories such as the GIA, HRD, IGI, EGL.
