The many ‘C’s’ of diamonds

Press, 1 September 1980, Page 25

The many ‘C’s’ of diamonds

What makes a diamond valuable? Is it impressive size,, the shape of the stone or the way in which it sparkles? Expert jewellers will tell you that several factors of equal importance determine how your diamond is priced. Jewellers refer to these

as the “Four C’s”, meaning Colour, Clarity, Cutting and Carat Weight. Of these, size or Carat Weight plays a minor part in determining value. Most important are the remaining three C’s — cutting quality, pure colour and flawless clarity — basic points to consider

and discuss with your jeweller when selecting your precious diamond. COLOUR Diamonds are judged according to their absence of colour, with the true, clear white being the most desirable. Below this standard most gem quality diamonds have a slightly yellowish cast to them, and it is the degree of this shading that affects value. As the colour deepens to a slight yellow tint, price falls accordingly. You may have heard or read about diamonds in rainbow colours blue, red, green, pink, canary yellow. Don’t expect to find these on display at your jeweller's. They are collector’s pieces with an appropriate value. Lately neutron bombardment and heat treatment have produced fancy colours, but such stones should only be sold as “artificially coloured”. Absence of colour remains the criterion for the dia-mond-buying public. CUTTING Most people associate cutting primarily with the shape of the diamond — round, square, marquise, oval — but to the crafts-man-jeweller there is much more to cutting than mere shape. The fire and brilliance of the diamond, admired through the ages, is

vealed only when It is scientifically cut to correct proportions, with precise angles, and with each facet highly polished. Poorly cut stones permit “light leakage’ ’and have a dulled, lifeless appearance. While you may let the shape of your hand and current fashion be your guide in selecting the style of diamond you purchase, do discuss with your jeweller the cutting of the' stone of your choice. Diamond cutting is an art. CLARITY It isn’t hard to understand why diamonds, having been created by the heat and pressure of prehistoric volcanoes, often contain imperfections of various kinds in their crystal structure. Very minute bubbles, whispy cracks or pinpoints of carbon (termed inclusions) may be visible only under 10-power magnification.

They do not detract from the intrinsic beauty of the gem but reduce its value depending on their number and size. Obvious flaws that can be seen at a glance naturally greatly affect both the quality and the durability of the stone. The clarity or relative clarity of your diamond is something your jeweller will discuss with you after examining the stone.