1. Colour

Diamonds are found with a range of colours, the rarest being colourless or fancy colours such as pink, red and blue. For a colourless stone, a letter is assigned to a colour grade. Each letter (from D to Z) on the scale describes a specific colour.

Many of these diamond colour distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.

International Standard of Colour Grading.

2. Clarity

The clarity of a colourless diamond is affected by the number of internal characteristics called ‘inclusions’ and external characteristics called ‘blemishes’ it contains.

Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.

Grading a colourless diamond for its clarity is done using an achromatic and an aplanatic loupe of 10 times magnification - (10x loupe).

The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.

• Flawless (FL) No inclusions and no blemishes visible under 10x magnification
• Internally Flawless (IF) No inclusions visible under 10x magnification
• Very, Very Slightly Included (VVS1 and VVS2) Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
• Very Slightly Included (VS1 and VS2) Inclusions are observed with effort under 10x magnification, but can be characterized as minor
• Slightly Included (SI1 and SI2) Inclusions are noticeable under 10x magnification
• Included (I1, I2, and I3) Inclusions are obvious under 10x magnification which may affect transparency and brilliance

3. Cut and Proportion

The cut refers to the shape in which the diamond is facetted e.g. Round Brilliant, Pear, Marquise, Baguette, Princess etc. The most common and preferred cut is the Round Brilliant Cut, (RBC).

Proportion refers to the specific angles and dimensions that are required during cutting and polishing to maximise the return of light from the diamond. It is an important factor when selecting a diamond. The above depicts an ideal RBC diamond with right proportions.

4. Carat Weight

Diamond carat weight is the measurement of how much a diamond weighs. A metric “carat” is defined as 200 milligrams or 0.2 grams.

Each carat can be subdivided into 100 ‘points.’ This allows very precise measurements to the hundredth decimal place. Diamond weights greater than one carat are expressed in carats and decimals. A round brilliant cut diamond of diameter 6.50 mm approximates to 1 Carat.

  One Carat = 0.2 Grams

  One Carat = 100 points

The picture is NOT to scale