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Buying Diamonds

How to Buy a Diamond

There are four factors that determine the value of a diamond, collectively known as the four C's.

The combination of the four C's determines each diamond's value. Master these important facts, and you will be prepared to make your purchase.

Carat

This word for the measurement of a diamond's weight is derived from the carob seeds that were used to balance scales in ancient times. A carat is equal to 200 milligrams, and there are 142 carats to an ounce. Carats are further divided into points. There are 100 points in a carat.A half-carat diamond may be referred to as a 50-point stone (about 100 milligrams). Because large diamonds are rare, they generally have a greater value per carat.

Colour 

Diamonds come in every colour of the spectrum, but the most popular gems are colourless. Truly colourless, icy-white diamonds are extremely rare and therefore the most costly.

Stones are graded by colour and given designations dependent on how far they deviate from the purest white. Colourless stones are graded D. Colour grading continues down through the alphabet, with each letter designating a yellower tint. The best way to see the true colour of a diamond is by looking at it against a white surface. Although the great majority of diamonds come in shades of white, the gems also come in a spectrum of majestic colours, from red and canary yellow to blue, green and brown. These colourful diamonds, known as fancies, are valued for their depth of colour, just as white diamonds are valued for their lack of colour.

 

 

Clarity

A diamond's clarity is affected by any external irregularities and internal imperfections created by nature when the diamond was formed. Imperfections such as spots or lines are called inclusions. Although these marks make each stone unique, the fewer the inclusions, the more valuable the stone. Inclusions can interfere with the passage of light through the stone, diminishing the sparkle and value of the diamond.

According to the quality analysis system of the CIBJO, clarity is graded on a scale ranging from internally flawless (IF) to imperfect (I). To be graded flawless, a diamond must have no inclusions visible to a trained eye under a 10x magnification in good light.

Cut

Each diamond is cut according to an exact mathematical formula. The most common cut, the round brilliant, has 58 facets, or small, flat, polished planes designed to yield the maximum amount of light to be reflected back to the viewer. This reflection, known as brilliance, is an extremely important factor in evaluating the quality of a diamond. A poorly cut diamond will actually lose light and appear dull. The widest circumference of a diamond is known as the girdle. Above the girdle of a brilliant cut diamond are 32 facets plus the table, the largest and topmost facet. Below the girdle are 24 facets plus the culet, or point. Cut is also used to describe the shape of a diamond. In addition to the round brilliant, other popular cuts include emerald, marquis, pear, oval and square.

Terms You Should Know

Just like the infinite range of diamond qualities and colours, there are many different shapes and setting techniques offered by today's designers.
Here is a mini-glossary of the most important ones:

Baguette - This refers to a rectangular-shaped small diamond that is often used to enhance the setting of a larger stone.

Bezel setting - A diamond is completely surrounded by a precious metal border in this setting technique that resembles a picture frame.

Channel setting - Popular for mounting rows of small, uniformly sized stones, this setting technique uses two strips of metal to hold the stones at the sides. Used for round, baguette and square-cut stones, the channel setting resembles a railroad track with the diamonds in the center.

Fancy cut - A diamond cut in any shape other than round. Fancy cuts include such shapes as baguette, emerald, triangle, pear, princess, oval and marquis.

Pavé setting - A setting technique for small diamonds in which the stones are set so closely together that no metal shows. A pavé surface appears to be paved with diamonds.

Solitaire - The mounting of a single gemstone.

Tiffany setting - A four- or six-prong setting using long, slender prongs to hold the stone.

Courtesy of the Retail Jewellers Of Ireland