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Diamonds -The Four Cs

Marilyn Monroe may have sung it but millions of women have proved it - diamonds really are a girl's best friend. by Kim McGuire

Ever since 1477, when Archduke Maximilian of Austria gave Mary of Burgundy a diamond engagement ring, the diamond has been the most popular gem for brides-about-to-be.

Two and three-stone diamond engagement rings were once preferred by Irish brides. Today things have changed: Irish women are more likely now to choose just one beautiful stone, mounted in either a yellow or white gold band. This shift in fashion reflects a similar trend which has been taking place for a number of years around the world: one that was initiated by the famous American store, Tiffany's, in the 1870s.

Diamonds are an investment and should be purchased wisely. A good jeweller will not only show you various shapes, colours and settings but will also explain the value of each stone. Most people believe that price is dependent upon size but, actually, a diamond's quality and cost is determined by it's cut, clarity, colour and carat. This system of classification is known in the jewellery trade as the Four C's.

When buying a diamond be sure that the stone has been certified by an independent gem laboratory. Two labs, the European Gemology Laboratory and the Gemological Institute of America, are the most highly regarded in the world. Certification should be provided at time of purchase and should describe the diamond's characteristics in detail.

Cut: Often confused with the shape of a diamond, "cut" actually refers to the many flat angled surfaces of the stone (called facets) which allow light to enter the diamond. The better the cut, the more brilliant the diamond will appear.

Clarity: All diamonds contain flaws (known also as inclusions, birthmarks or debris) but the fewer there are the better. Flaws interfere with light passing through a diamond, making it appear less brilliant. Less than 1% of all diamonds are flawless. The system of grading a stone is:

  • IF for internally flawless (it is extremely difficult to find any debris or inclusions, even under magnification);
  • VVS for very very slightly included;
  • VS1 for very slightly included;
  • SI1 for slightly included (the diamond should still look perfect to the naked eye) and;
  • I for included (it is fairly easy to find imperfections with the naked eye).

Colour: Most diamonds have some colour but the better the stone, the less evident the colour is. Colour is determined on a graduated scale. D to F is almost perfect or colourless; G to J is near colourless; and from K to Z the colour increases by degree.

Carat: The size and weight of a diamond is measured in carats. One carat is equal to 1/5 of a gram and is referred to as being made up of 100 "points". Good quality stones of more than one carat are rare.


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