Diamonds - their very mention makes the heart skip a beat. Be it for the expectations implied or for the very beauty and exquisiteness of their possession. However, purchasing a diamond can test the nerves of even the most astute buyer - what do you look for? What do the terms mean? What makes one diamond worth more than another?

Here is a simple guide to the essentials of diamond grading. Understanding these terms will help you discuss with the dealer the features most important to you, ensuring you get the very best diamond for your money.

Diamond appraisers look for four qualities in a diamond when discerning its value. Commonly called the '4 Cs' they are: Cut, Clarity, Carat and Color.

Picking a diamond is something much more personal than finances

CUT

There are two aspects referred to when discussing the cut of a diamond. The first refers to the quality of the cut - affecting the brilliance of the diamond - the other refers to the actual shape of the diamond.

Diamonds are available in many shapes. Some of the more common are; round, oval, pear (teardrop shaped), heart, princess (square shaped), Emerald (rectangular shaped), marquise (football shaped) and round.

Of all the shapes available, round diamonds are the shape most capable of being cut to exude the greatest brilliance. The brilliance is determined by the ability of the diamond to reflect light. A quality cut diamond will have facets angled to reflect the greatest amount of light. Beware of diamonds cut to maintain a higher carat weight while sacrificing the cutting of a good angle as this will dramatically reduce the brilliance.

CLARITY

Diamonds from natural sources are subject to individual flaws including trace minerals and scratches. A diamond without such characteristics is called flawless and is the rarest kind. While these flaws are often not visible to the naked eye, they affect the light reflecting qualities of the diamond which affects the overall brilliance.

Diamond clarity is classified as follows: Flawless, IF, VVS1, VVS2, VS1, VS2, SI1, SI2, SI3, I1, I2 and I3.

A reliable jeweler is a diamond expert and will be happy to explain how to choose a diamond

CARAT

Carat is the measurement of the weight of a diamond. One carat may also be referred to as '100 points'. This means that a half carat would be listed as '50 points' and so on.

The larger a diamond is the more costly it becomes. Since the larger diamonds are much rarer the cost will go up significantly with each increase in size. A one carat diamond will be more than just double the cost of a half carat, however, a ring with multiple diamonds that have a combined weight of one carat will be cheaper than a single stone of that weight.

COLOR

The color of a diamond is rated on an alphabetical scale from D to Z. A typical 'white' diamond should be as colorless as possible - a rating of 'D' being the rarest and most desirable. When choosing a colorless diamond it is best to stay within the D-J range or the diamond will have a yellow cast which lessens the value. The less natural color the diamond has the more colors will appear in the flashes reflected in the prism.

'Fancy' diamonds (diamonds with a rating over Z) come in a variety of shades and include some famous diamonds such as the Blue Hope diamond.

When purchasing a diamond it is important to remember that each of the 4 Cs are of equal importance in an appraiser's eyes. If budget is an issue, however, you should consider which features are of greatest importance to you and with a little knowledge select the diamond that will hold the greatest value and sentiment for your budget.