Colour

A diamond’s colour is important because it has a direct effect on how light behaves when it enters and exits the stone. A colourless diamond allows light to enter, disperse and exit without interference, producing a brightness and fire that is outstanding. A diamond with a tint of colour, caused in the most part by the existence of nitrogen will cause interference and some of the light will be absorbed. The greater the amount of colour, the less brightness and fire a stone will produce.

GIA’s , IGI & HRD’s colour-grading scale for diamonds is the industry standard. Each letter grade has a clearly defined range of colour appearance. Diamonds are colour-graded by comparing them to stones of known colour under controlled lighting and precise viewing conditions. Many of these colour distinctions are so subtle that they are not visible to the untrained eye. However, these slight differences make a very big difference in diamond quality and price.

Colour Grading

GIA’s , IGI & HRD’s colour-grading scale for diamonds is the industry standard. Each letter grade has a clearly defined range of colour appearance. Diamonds are colour-graded by comparing them to stones of known colour under controlled lighting and precise viewing conditions. Many of these colour distinctions are so subtle that they are not visible to the untrained eye. However, these slight differences make a very big difference in diamond quality and price.

Unique and Rare Colours

When a diamond has a unique or rare colour it becomes desirable and valuable, based on the shade and intensity of colour.

The range of desirable coloured diamonds includes:

  • Canary yellow
  • Blue
  • Red
  • Pink

Selecting the colour of your diamond

The best colour grade for your diamond needs depends on various factors; including shape, cut, clarity, carat weight and the amount of money you wish to spend. Here are a few suggestions to consider:

  • If you want an exceptional quality diamond with excellent fire, select a diamond with a colourless grade of D, E, or F.
  • If you want an excellent diamond that represents good value for your money, select a diamond with a near-colourless grade of G or H.
  • If you want a high colour grade but are on a limited budget, select a diamond with a cut grade of good, clarity grade of SI1 or SI2 and a shape that accentuates brilliance.
  • Invest in the highest quality diamond (in terms of the four C’s) that you can afford.

What about fluorescence?

The range of fluorescence (very strong, strong, medium, negligible, faint, inert, or none) causes different effects depending on the four C’s of a diamond and the light in which it is viewed. In some situations it can cause a colourless or near-colourless diamond to appear exceptionally bright, while in other situations it can cause the same diamond to appear foggy, oily, hazy or milky.

In general, a diamond with a fluorescence of medium or less will not show noticeable effects. Fluorescence of strong or very strong can lower the value of a diamond.

Why does the GIA approved colour grading system start at D?

Prior to the renowned GIA developed D-Z Colour Grading Scale, a variety of other systems were loosely applied. These included letters of the alphabet (A, B and C, with multiple A’s for the best stones), Arabic (0, 1, 2, 3), Roman numerals (I, II, III), and descriptions such as “gem blue” or “blue white.” The results of these grading systems were often inconsistent and inaccurate. The creators of the GIA Colour Scale wanted to start afresh, without association with other systems; therefore they chose to start with the letter D—a letter grade not normally associated with top quality.

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