Diamonds form under great pressure and intense heat deep below
the earth at volcanic sites. They are brought to the surface through the
eruptions and often washed into river beds. Diamonds grow in a cubic system and
have a hardness of 10 on the moh’s scale.
Diamonds are found in many colours. This is due to impurities in the earth at the time of formation.
“Diamonds form in a cubic system as pure carbon or nearly pure carbon, other influences can produce
very rare coloured diamonds. Tiny amounts of other elements can cause natural colours in these beautiful
stones such as nitrogen in yellow diamonds, boran in blue diamonds and high energy radiation over thousands
or even billions of years in green diamonds. Diamonds form at unimaginable pressures of more than
45,000 times that of the Earth’s atmosphere and at temperatures exceeding 950 degrees centigrade.”
(From: ‘Natural History Museum’ exhibition 08.07.05 to 26.02.06.)
However, technology has now allowed Diamonds to be treated to change the colour.
Diamond Chart
The 4 “C’s”
Colour
Diamonds range from colourless though tints of colour
until completely saturated and classed as a fancy colour. This is mainly seen in
yellow or brown diamonds often called canary yellow or cognac Diamonds.
Please see chart
Clarity
This refers to a Diamonds optical quality. Grading is based on
the number, size and visability of internal flaws and imperfections called
inclusions.
Please see chart
Cut
The cut determines both the shape and fire in the stone. A well
cut Diamond will show it’s best fire and brilliance as the light refracts off of
it’s facets.
Diamonds are cut in the following shapes: Round Brilliant,
Princess cut (Square), Emerald cut, Oval, Pear shaped, and marquise, to name a
few.
Carat
Carat refers to the weight of the diamond. There are 100 points
in a carat.
For example: half a carat (50pts) is written 0.50ct, where as
5pts is written 0.05ct, and half a point is written 0.005ct.
All diamonds are priced on the above factors. The larger, whiter,
cleaner and more brilliance a Diamond has, the higher the value.
