GIA 4 Cs Guide To Diamonds

Diamond Grading Report

A GIA Diamond Grading Report includes an assessment of the 4 Cs – Colour, Clarity, Cut and Carat Weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. The report also includes the official GIA grading scales for Colour, Clarity and Cut as reference tools.

  • Colour
  • Clarity
  • Cut
  • Carat Weight

For more than 50 years, fine jewellers everywhere have considered the GIA Diamond Grading Report the premier credential of a diamond’s authenticity and quality.

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The Quality of a Diamond

The quality of a diamond is determined by a number of different methods including the famous 4 C s of diamond grading (Cut, Colour, Clarity and Carat Weight). This diamond grading system provides an excellent guide to the quality of a diamond. The numbers, sizes, colours, locations and visibility of any inclusions and / or blemishes in a diamond can also affect the grading and quality of a diamond.

This page details the grading systems and charts relating to diamond clarity, colour grading for white or colourless diamonds, carat weight and a diamond fluorescence grading chart.

Clarity Grading

The majority of Diamond inclusions cannot be seen by the human eye so systems have been developed to grade diamond clarity. The different types of diamond grades reflecting clarity are detailed on the Diamond Clarity Chart. Diamond grading on a Diamond Clarity Chart ranges from high quality, rare and expensive flawless to imperfect and cheap diamonds.

As the majority of inclusions cannot be seen by the naked eye, they are located by a jeweller under a 10 power magnification and then graded according to their clarity. The grading and levels are described on the Clarity Chart. An excellent grading guide when choosing diamonds.

Colour Grading

White coloured, or colourless, diamonds are categorised into the following: Colourless, Nearly colourless, Faintly tinted (usually yellow), Lightly tinted (usually yellow) and Tinted (usually yellow but may progress to brownish).

The scale and grading for colourless diamonds goes from ‘D’ (colourless) to ‘Z’ (dark yellow). The less colour, the more expensive.

Carat Weight

The size of a diamond relates to the proportions, dimensions or measurement in terms of length, width and height.

In diamond grading, the carat weight is the standard unit of measure that defines the actual weight of a diamond. A Carat is a standard unit of weight for diamonds. In diamond grading carat weights are also expressed as “points” with a one carat diamond equalling 100 points.