Clarity

"A matter that becomes clear ceases to concern us," said Nietzsche. While the renowned philosopher was probably not referring to diamonds with that observation, his point was well taken. When a diamond's clarity is assured, all of the other three Cs fall into place.

What exactly is clarity and why is it so important, you may well ask? Technically, a diamond's sparkle comes from its ability to reflect and refract light. How the diamond achieves this is both magical and scientific, dependent on both the natural characteristics of the stone and the effectiveness of its cut.

Light it Up
It all begins when a beam of light touches the surface of a diamond and part of the ray is reflected back to the viewer. As the rest of the ray penetrates the stone, it is refracted or bent, by the stone's density, reflected from the internal surfaces of the stone and back out the top. At this point, the beam is again refracted, breaking into the rainbow colors of the spectrum, a phenomenon known as dispersion. It is in this last stage that the diamond's fire and sparkle are visible.

All these activities indicate why the greater a stone's clarity, the greater its brilliance. Therefore, the most valuable white diamonds are those that are very clear and virtually colorless.

A diamond's clarity is determined by any external irregularities and the number of "inclusions" in the stone--that is, imperfections created by nature when the diamond was formed. Remember, these gems were formed deep within the earth's core more than 100 million years ago and brought to the surface by volcanic eruption.

As a result, most diamonds do contain some inclusions, formed during their crystallization process, but many are microscopic in nature and can be glimpsed only under powerful magnification. When inclusions do not interfere with the passage of light through the stone, they do not affect its beauty.

Making the Grade
Inclusions such as spots, bubbles or lines are marks that make each stone unique, but generally speaking, the fewer the inclusions, the more valuable the stone. According to the quality analysis system of the Gemological Institute of America, clarity is graded on a scale ranging from "flawless" to "imperfect." To be graded "flawless," a diamond can have no internal or external inclusions. The next grade, IF, meaning internally flawless, indicates that a diamond might have minor surface blemishes but is internally clear.

The next lower grade for diamonds is VVS (1 and 2), or very very slight inclusions, which are difficult to see without magnification. These are followed by VS (1 and 2), signifying very slight inclusions to SI, (1, 2 and 3) for slight inclusions. The succeeding grades of I 1, I 2 and I 3 indicate inclusions that are visible under 10x magnification as well as to the naked eye. (Don't bother looking at any gem under more than 10x magnification for other than curiosity's sake. What you will see under higher magnification will not affect the beauty of the stone.)

You may not always be able to see the difference between stones that are similarly graded or even a grade apart, but understand that a diamond's value decreases with each downgrading of clarity. For example, the difference in price between a VS 1 quality stone and an SI 1 can be as much as 20%, all other things being equal.

Of course, the degree of clarity will be determined by your budget and preference, but the most common grades in jewelry range from flawless to SI. Lower grade stones are more common in fashion jewelry rather than in engagement rings.

While the shape of a diamond does not influence its quality, certain shapes might reveal additional inclusions. For example, an emerald cut, with its elongated facets and flat table, is more likely than other shapes to reveal a poor color grade or many inclusions.

What it Means
Your certificate is an important tool for evaluating the clarity of your diamond because many flaws are invisible to the naked eye, making it easy to make mistakes. The laboratory grading the stone uses expert graders and highly sophisticated gemological instruments. Clarity is judged by the number, placement and nature of inclusions visible under 10X magnification.

A plot of your stone showing the top and bottom views may be included to illustrate the exact placement of the stone's internal and external markings. Like human fingerprints, these designs imprinted by nature into your diamond are what set your stone apart from all others.