Gemstone & Diamond Guide

Do you really know what type of diamond you want on your ring? Find out everything you need to know about a diamond's carat, color, cut, and clarity (the 4C's) to help you buy the perfect sparkle.

Buying a diamonds for that special person in your life is an exciting experience. To get the best value for your money, you need to know what makes a diamond unique. We will help you understand about what factors affect a diamonds price.

Diamond Carat Weight

Although commonly thought to refer to the actual size of a diamond, a carat is actually a standard unit of measure that defines the weight of a diamond. One carat is equivalent to 200 milligrams. Carat sizes are also expressed as "points", with a one carat diamond equaling 100 points, a one-half carat diamond being 50 points, a three-quarter carat diamond being 75 points, and so on. (Don't confuse carat with karat, as in "18K gold", which refers to gold purity.)

The most common Carat weights and their corresponding "points":

One Carat = 100 points
Three-quarters Carat (3/4 Carat, 0.75 Carat) = 75 points
Half-Carat (1/2 Carat, 0.50 Carat) = 50 points
Quarter Carat (1/4 Carat, 0.25 Carat) = 25 points
Melee - tiny stones used in pave or channel settings. Usually weigh 0.15 carats (15 points) or less and are either grouped together or used to augment a larger stone.

Larger diamonds are rarer than smaller ones and are therefore more expensive. However, two diamonds of equal weight can have very different values depending on the other members of the Four C's: clarity, color and cut. The majority of diamonds used in fine jewelry weigh one carat or less. Be careful about shopping for the largest diamond without consideration of the other value factors.

Diamond Color

While most people think of diamonds as being white or colorless, they come in every color you could think of. Diamonds are valued by how closely they approach colorlessness - the less color, the higher their value.

Although the great majority of diamonds come in shades of white, there are also "fancy" natural colored diamonds in red, pink, blue, green, yellow, brown, and other colors. The value of a fancy diamond depends largely on the rarity of its color (for instance, reds and greens are rarer than yellows and browns); the saturation of the color; and the purity of the color (whether the color is bright and clear or clouded by tinges of other underlying colors).

Although, fancy colored diamonds rarely occur in nature, laboratories can easily create them through irradiation and heating. This process can permanently turn a natural colorless diamond into a fancy diamond in a wide range of colors. Treatments have also been developed to make lower-color white diamonds whiter. Irradiated colored diamonds have a significantly lower value than natural fancy diamonds and can be detected in a gem laboratory.

Most diamonds are graded on the GIA color scale that begins with "D" for colorless and continues all the way down to "Z," for near-colorless. Stones in the D-F color ranges are considered the most valuable because they are the rarest. Here are the color ranges for white diamonds, based on how visible its body tint is to the naked eye:

D - F - Colorless
G - J - Near colorless - visible only to a trained eye.
K - M - Small stones are colorless; larger stones are tinted.
N - R - Stones show an increasing tint of color, even to an untrained eye.
S - Z - Stones appear yellow, even to an untrained eye.

You can still obtain great value (and save money) with diamonds graded G - J, since no color is visible to the untrained eye. As a quick tip, yellow metal (gold) hides traces of color in a colorless diamond, while white metals (white gold, platinum, silver) will enhance it.

Diamond Clarity

A diamond's clarity refers to the presence of identifying characteristics on and within the diamond. While most of these clarity characteristics are inherent qualities of the diamond and have been present since the earliest stages of the diamond crystal's growth within the Earth, some diamond flaws are actually a result of the harsh stress that a diamond undergoes during the cutting process itself including scratches, blemishes, air bubbles or non-diamond mineral material. Diamonds with no or few inclusions and blemishes are more highly valued than those with less clarity, not just because they are more pleasing to the eye, but also because they are very rare.

Clarity grades range from Internally Flawless, diamonds which are completely free of blemishes and inclusions even under 10x magnification, to Imperfect 3, diamonds which possess large, heavy blemishes and inclusions that are visible to the naked eye.

There are several types of inclusions and blemishes, which affect a diamond's clarity to varying degrees. Features resulting from diamond enhancement procedures, such as laser lines, are also considered inclusions or blemishes. Inclusions/Blemishes includes: Clouds, Feathers, Knots, Cavities, Cleavage, Bearding, Internal graining Polish lines, Grain boundaries, Naturals, Scratches, Nicks, Pits, and Chips.

Clarity Types

Flawless (FL) - No external marks or internal inclusions visible to a trained eye under 10x magnification.
Internally Flawless (IF) - Only minor surface blemishes but no internal inclusions visible to a trained eye under 10x magnification.
Very, Very Slightly Included (VVS1 and VVS2) - Few, very small inclusions and/or finish faults, difficult for a trained eye to see under 10x magnification. Typical flaws include tiny pinpoints, faint clouds, tiny feathers, or internal graining.
Very Slightly Included (VS1 and VS2) - Very small inclusions and/or finish faults, somewhat difficult for a trained eye to see under 10x magnification. Typical flaws include crystals, feathers, distinct clouds and groupings of pinpoints.
Slightly Included (SI1 and SI2) - Small inclusions and/or surface blemishes easily seen under 10x magnification, but not visible face-up to a naked trained eye. Typical flaws include crystals, clouds and feathers.
Included (I1, I2, and I3) - Inclusions and surface faults easily seen without 10x magnification.

Diamond Cut

A diamond cut refers to the execution of a diamond's design, the skill with which it was cut, the quality of its polish, and the overall symmetry of the stone. Key factors include the stone's roundness, depth, width, and the uniformity of its facets. In short, what we generally think what makes a diamond sparkle.

A diamond's cut grade is an objective measure of a diamond's light performance, or, what we generally think of as sparkle. When a diamond is cut with the proper proportions, light is returned out of the top of the diamond. If it is cut too shallow, light leaks out of the bottom; too deep and it escapes out of the side.

The better the proportion of the diamond is, the better the light reflection. The most spectacular, and costly, diamonds are the ones that are more perfectly proportioned. A shallow cut diamond, for example, where the bottom half lacks a certain depth, will not reflect light in the most optimal way.

Although there are several systems for determining the quality of a diamond's cut, they can be usually classified as Ideal, Very Good, Good, Fair or Poor. However, the difference between Ideal Cut and Poor Cut can be difficult to notice by the untrained eye. The diamond cut is so important that several grading methods have been developed to help consumers determine the cut of a particular diamond. In general, these grades are:

Ideal - This cut is intended to maximize brilliance, and the typically smaller table sizes of these diamonds have the added benefit of creating a great deal of dispersion or 'fire' as well. Ideal quality diamonds are truly for the person who enjoys knowing that he has one of the finest things that money can buy. This category applies only to round diamonds.
Very Good - These diamonds reflect most of the light that enters them, creating a good deal of brilliance. With these diamonds, the cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond.
Good - Diamonds that reflect much of the light that enters them. Their proportions fall outside of the preferred range because the cutter has chosen to create the largest possible diamond from the original rough crystal, rather than cutting extra weight off to create a smaller, better quality diamond. Diamonds in this range offer an excellent cost-savings to customers who want to stay in a budget without sacrificing quality or beauty.
Fair & Poor - A diamond graded as fair or poor reflects only a small proportion of the light that enters it. Typically these diamonds have been cut to maximize the carat weight over most other considerations. You can find these cut diamonds in retail malls and online jewelry websites.