Diamonds are the ubiquitous gemstone, the one that is easily recognisable and at the top of most peoples lists when it comes to desirable jewellery. Diamonds have many qualities that place them at the top of the pile, the first one is, of course, their beauty.
In 1919 Marcel Tolkowsky focused on the round cut of the diamond and performed a series of calculations to determine the perfect proportions for a diamond to maximise the fire and sparkle in the stone. His calculations are the basis for the cutting that is done today. The date is seen as a landmark for modern modern diamond jewellery design, stepping beyond the visual into mathematics. There is a marked difference in the shape of the stone and his techniques became highly refined resulting in the intense beauty that we expect today.
The colour range that plays through the centre of a diamond is known as the fire. Fire is a characteristic that is only revealed when a high dispersion of light is achieved in the stone. The more successful the flow of light is the more fire there will be in the stone. The flow of light is maximised by a good cut, a stone with minimal inclusions in it and is best seen in a diamond of a good size.
Diamond is a natural product, it formed in the ground over millions of years, the process left, in almost all instances, small inclusions in the stones. The inclusions look like specks of black dirt trapped within the stone. Inclusions devalue a stone. The best stones have no inclusions but they are very rare, most people are happy with a diamond with no visible inclusions when looked at with the eye or diamonds with small inclusions that do not detract from the overall appearance of the stone.
Coloured diamonds, also known as fancy diamonds, are currently growing in popularity. Colour is defined by gemmologists in three ways, saturation, hue and tone. This trio provides a means of identifying the best gemstones and allowing all gemstones to be clearly defined and traded at their relative value. The Gemmological Association of America provides the details of how to apply the three terms, their standard is used worldwide. Hue is the colour itself, tone refers to the lightness or darkness of the colour and saturation is the strength or depth of colour. The three descriptors can be used as a sliding scale which allow for accurate definition of colour. The proper grading of gemstones always takes place under strict controls on environment, including lighting, magnification and accepted colour comparators.
Diamonds are most readily available in white colour but they are also available in a range of other colours including pink, red, blue, yellow, orange and brown.
It is important to remember that gemstones are natural products, they display variation and imperfections. In emerald, which almost always displays inclusions, the internal variations are known as a garden. This is part of their character and their charm and distinguishes them from mass produced imitations that lack the intrigue and true beauty of the real thing.