Education - Diamonds
White Diamonds
White diamonds are graded in relation to 4 main properties, the Cut, Colour, Clarity and Carat. These specifications are often referred to as "The 4 C's". The process of grading white diamonds in this way was developed by the Gemological Institute of America (GIA), and it is now considered a standard grading process the world over.
Every white diamond that is graded by GSL is assessed in relation to the 4 C's. It is these characteristics that determine the final grade of a diamond, with the grades then directly relating to the market value of any given diamond.
If you are interested in further information or would like to undertake a course in Diamond Grading, please contact the Gemmological Association of Australia.
Every white diamond that is graded by GSL is assessed in relation to the 4 C's. It is these characteristics that determine the final grade of a diamond, with the grades then directly relating to the market value of any given diamond.
If you are interested in further information or would like to undertake a course in Diamond Grading, please contact the Gemmological Association of Australia.
Cut
The cut (or "make) of a white diamond is arguably the most important feature of a diamond. The cut grade does not refer to the shape of a diamond (each shape has a different set of standards relating to the quality of the cut grade), but rather it refers to the proportions and angles of the facets and how they combine to produce a lively sparkling diamond with maximum return of light to the observer's eye. It is the cutting standards that directly relate to the brilliance or "sparkle" of a diamond. Regardless of how high the the Colour and Clarity grades of a diamond may be, if the diamond is not cut well it simply will not show a high level of brilliance.
If a diamond is cut well, the light entering the stone will be internally reflected from one facet to another, resulting in the reflection of the light out of the top of the stone. It is this reflection of light that is referred to as the "brilliance".
When light exits the stone it also splits into the different colours of the spectrum creating the little coloured sparkles that are referred to as the "fire".
If a diamond is cut too deep, the light entering the stone will be lost through the bottom facets, resulting in the diamond appearing dark. Similarly, if a stone is cut too shallow, the light will also escape through the bottom facets, resulting in a watery or glassy appearance.
Well cut diamonds follow strict mathematical guidelines, with each diamond shape having a different set of mathematical standards relating to the correct proportions for maximum brilliance and fire.
If a diamond is cut well, the light entering the stone will be internally reflected from one facet to another, resulting in the reflection of the light out of the top of the stone. It is this reflection of light that is referred to as the "brilliance".
When light exits the stone it also splits into the different colours of the spectrum creating the little coloured sparkles that are referred to as the "fire".
If a diamond is cut too deep, the light entering the stone will be lost through the bottom facets, resulting in the diamond appearing dark. Similarly, if a stone is cut too shallow, the light will also escape through the bottom facets, resulting in a watery or glassy appearance.
Well cut diamonds follow strict mathematical guidelines, with each diamond shape having a different set of mathematical standards relating to the correct proportions for maximum brilliance and fire.
Colour
D E F G H I J K L M N O
"White" diamonds, although appearing colourless to the naked eye, can have slight tones of yellow and sometimes brown and even combinations of the two body colours. As the tones of colour become more obvious, the Colour grade of a diamond decreases.
High Colour grades therefore refer to stones that draw the least colour. The Colour grade scale goes from D - Z, with D colour stones being completely colourless. Stones that draw more colour than Z are then referred to as Fancy Colour Diamonds (see Education - Fancy Colour Diamonds).
High Colour grades therefore refer to stones that draw the least colour. The Colour grade scale goes from D - Z, with D colour stones being completely colourless. Stones that draw more colour than Z are then referred to as Fancy Colour Diamonds (see Education - Fancy Colour Diamonds).
Clarity
The Clarity grade of a diamond refers to the presence, size, type, number and location of any internal inclusions or external markings seen in a diamond. A stone is graded face up and under 10x magnification. The Clarity scale ranges from Flawless (FL) to Pique (eye visible).
Carat
Carat refers to the weight of the diamond. One carat is equal to 200 milligrams. When weighing diamonds, Carat is further broken down into points, with 100 points equal to 1 carat.
Diamond weight is always recorded in Carats, to two decimal places. For example, a stone weighing half a carat (or 50 points) would be described as 0.50ct.
Diamond weight is always recorded in Carats, to two decimal places. For example, a stone weighing half a carat (or 50 points) would be described as 0.50ct.