Colours of Diamonds - 1 page.

 The multitude of diamond colours will be described in this essay. Diamonds are separated into four distinct characteristics: CUT, COLOUR, CLARITY and CARAT.

 "Carat" is actually a weight measurement, but since the density of a diamond is quite constant, the weight can be reasonably translated into size. DO NOT MIX THIS NAME WITH 'KARAT'. Karat refers to the quality designation of gold, as in 18-karat gold.

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COLOUR: 

 "D - E - F". These are absolutely "colourless".                           

"G - H - I - J". These are "near colourless".

"K - L - M". These are "faint of colour".                 

"N - O - P - Q - R". Named "very light yellow".

"S - T - U -V- W - X - Y - Z".  Or "light yellow".

"Z". These have a "fancy yellow" colouring.

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CLARITY: 

FL. Means that these are "Flawless".

IF. These are "Internally Flawless".

VVS1, VVS2. These stones have "Very, Very Slight Inclusions".

VS1, VS2. The stones have "Very Slight Inclusions".

S1, S2. Means that there are "Slight Inclusions".

I1, I2, I3. These stones are named "Imperfect".

The above are observed under a 10x power magnification Loupe.

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SIZE:

In a round diamond, a 0.1 carat stone is equivalent to 3.0 mms or 0.118 inches. 

CUT:

'Cut' has the greatest influence on a diamond's fire & brilliance. A "Round Brilliant-Cut" diamond (RBC) has 58 facets. 

When it is well proportioned, this shape best shows the stone's brilliance because it allows the most light to be reflected back to the eye of the observer. Stones that appear lifeless or seem dark in the centre are named 'Poor Cut'.

When the relationship of the angle between the Crown and the Pavilion is correct, the rays of light entering the diamond strike the rear Facets at an angle greater than the critical angle of (24.5 degrees for a diamond) and reflect back to the eye of the observer. 

If the angle of the stone is cut too deeply, the light strikes the rear Facet at an angle less than <24.5 degrees, then the important light is lost through the sides of the stone.

If the stone is cut too shallow, the important light passes right through the diamond without being reflected back...and this appears to be a 'black diamond'. (I've personally seen this & it isn't nice to look at.)