Cut
Many gemologists consider cutting quality to be the most important diamond characteristic because even if a diamond has perfect color and clarity, a diamond with a poor cut will have reduced brilliance. Cut is not shape, i.e., pear, round, oval. Cut refers to the quality of the proportioning, polish, and symmetry.

Generally speaking, there is some agreement on how round brilliant-cut diamonds should be cut to optimize brilliance and dispersion. However, there is no universal standard as to what constitutes the "ultimate" or "perfect" proportions for a round brilliant.

The width and depth have the greatest effect on how light travels within the diamond, and how it exits in the form of brilliance. As cutting quality can be a confusing subject, you should ask your professional jeweler about "ideal" proportions and request a cut grading report from a major independent gemological laboratory.

Diameter: The width of the diamond as measured through the girdle.

Table: The flat top and largest facet of a diamond.

Girdle: The narrow band around the widest part of a diamond.

Pavilion: The bottom portion of a diamond, extending from the girdle to the point of the stone.

Culet: The facet at the tip of a diamond. The preferred culet is not visible with the unaided eye.

Depth: The height of a diamond measured from the culet to the table.


Here's a model for one "ideal cut" diamond based on a set of proportions proposed by a mathematician named Marcel Tolkowsky in 1919. While today's cut standards are still based on this model, there have been deviations that produce very beautiful diamonds. There is still no universal agreement on the "ultimate ideal cut" for a diamond.



Color
Color is personal: some people like a diamond with an ice-cold whiteness (colorless or near-colorless), while others prefer the golden glow of a warmer color. Diamonds with no color like D, E, F, are very rare and are more expensive than near-colorless (G, H, I, J) diamonds.

Diamonds with a faint tinge of color (K, L, M, N, O) have a slightly warm color and are more affordable. For those who want a larger diamond within a certain budget, selecting diamonds with a lower color grade may be the best option.

Less color is generally preferred but "fancy" is rare. Did you know that diamonds come in every color of the rainbow? These rare "fancy colors" are, carat for carat the most expensive objects on the entire earth. Some of the highest prices paid per carat are for colored diamonds.

Fancy colors include brilliant yellows, steely blues, soft pinks, fiery oranges and more; there's even fancy white and black. If the color is natural, as opposed to treated, the prices of these fancies can be extremely high.
 

Above is the official color grading scale recognized by the international diamond trade and trade certification laboratories. The scale runs in order of rarity from colorless on the left to light yellow on the right.

Clarity
Clarity refers to how free a diamond is from nature's "birthmarks," or tiny, generally microscopic imperfections that make each diamond unique.

Diamonds are assigned clarity grades based on what can be detected with ten-power (10x) magnification. If there's a microscopic piece of dust on a diamond, it affects the clarity grade. Most internal features (inclusions) and external features (blemishes) in the diamond have little or no effect on brilliance and fire.

So, if small clarity characteristics don't affect a diamond's beauty, why are diamonds with higher clarity grade so expensive? It's simply because diamonds with relatively few clarity characteristics are very rare. Fortunately, diamonds of all clarity grades and prices, including those with eye-visible inclusions, can look beautiful depending on how well they're cut and other factors. The best advice is to look at several diamonds of different clarity grades and let your eye be the guide!
 

The charts above will provide the definition of clarity grades and give you some idea of how clarity grades compare to one another. Remember, trained professionals perform clarity grading under ten-power binocular magnification and the average person would have a harder time locating clarity characteristics.

Carat Weight
Carat is the measure of weight of a diamond. 1 Carat = 0.2 grams or 0.007 ounce. The weight of the diamond and the price per carat determines the price of a diamond.

Total Price = Weight x Price per Carat

All other things being equal, a larger diamond is rarer, and more expensive, than a smaller one. However, since the weight of a diamond is distributed all over its surface, a two-carat diamond doesn't look twice as big as a one-carat diamond. In other words, a lot of the weight of a diamond isn't necessarily where you can appreciate it.


 

Take a look at the chart above and see for yourself.

Although many people equate "bigger" with "better," diamonds of all sizes have the potential to be lively, exciting and beautiful. The most important thing is to buy the one that's right for you.

To choose the ideal carat weight, consider the following:

• The recipient's personal style, finger size, and the size and style of the setting.
  
   
• Keep in mind that the smaller the finger, the larger the diamond will appear. A 1 ½-carat diamond solitaire looks much larger on a size 4 finger than a size 8.
  
   
• If you have already chosen a setting, make sure you choose a diamond that looks appropriate in the ring.