Red, blue, green, purple—the concept of color seems simple, right? Not when it comes to gemstones. In fact, color is a crucial and extremely nuanced part of gemstone evaluation, as it can vary significantly from variety to variety (such as an amethyst and a ruby) and even within varieties. Hue, tone, and saturation all contribute to the unique color of a gemstone. Hue refers to the traditionally understood color we would assign to a gemstone, with ideally colored gemstones possessing a main color and only minor hues of other colors. Tone describes how deep the gemstone's color is, using a scale that spans from colorless all the way to black. Saturation refers to the intensity of a gemstone's color. The less brown and gray hues in a gemstone, the stronger the saturation. With the majority of colored gemstones, value is usually placed on medium tone, rich color saturation, and vibrant color. A specific diamond color scale is used to evaluate white diamond color.
The type and quality of a cut is also an important factor in selecting gemstone jewelry. You'll quickly find that you have plenty of options, whether you're deciding between cuts of a sapphire for a pendant or types of diamond cuts for a wedding band—like a princess cut diamond or a round cut diamond. A well-chosen and well-executed cut can help enhance the beauty of a gemstone of any carat size by highlighting its color and luster.
The objectivity of rating gemstone cuts has been debated within the industry. No standards exist for colored gemstones; however, the Gemological Institute of America (GIA) has developed an evaluation system specifically for diamond cuts. That system grades these cuts among five categories: Excellent, Very Good, Good, Fair, or Poor.
Whether you're examining different diamond cuts or cuts of other gemstones, you can be your own judge of cut quality by comparing similar gemstones side by side. When a gemstone is cut skillfully, it will reveal consistent color and appear symmetrical. A good cut can also help conceal inclusions. You should also be able to see most of the carat weight when looking at it from above.
Gemstones can be cut in a wide variety of styles. Some cuts are more suited to particular gemstones and particular gemstone varieties than others. Read below for more details about specific cuts.
Gemstones typically have flaws because of their natural formation process. Called inclusions or blemishes, these flaws may manifest themselves as cloudiness, as fractures, and in other forms. When it comes to evaluating a gemstone for clarity, it's important to consider the variety of the gemstone. It's tolerable for certain varieties of gemstones, like rubies, to have more inclusions than other varieties. Valuable and rare is the colored gemstone with few inclusions or none at all. Similarly, under 10x magnification, no diamond is perfect. Even those that are almost perfect are incredibly uncommon. While there are many diamond cuts and diamond shapes, whether you're examining a princess cut diamond or a cushion cut diamond, it's prudent to expect some degree of flaw in a diamond of any carat size.
The Gemological Institute of America created a system to evaluate diamond clarity called the GIA Clarity Scale. There are 11 grades in this diamond clarity scale, with Flawless diamonds ranking highest in clarity and Included diamonds with an I3 grade ranking lowest. For a more detailed explanation of each grade, read the diamond clarity chart below. Keep in mind that these criteria apply to a diamond examined under 10X magnification by someone trained in grading.
Inclusions or blemishes cannot be seen in the diamond.
Blemishes can be seen in the diamond, but not inclusions.
Very, Very Slightly Included
Evaluator has trouble seeing inclusions in a diamond. Very, Very Slightly Included diamonds can fall into two grades: VVS1 and VVS2.
Very Slightly Included
Diamond has minor inclusions that the evaluator may find somewhat easy or difficult to find. Very Slightly Included diamonds can fall into two grades: VS1 and VS2.
Diamond has inclusions that can be easily seen by the evaluator. Slightly Included diamonds can fall into two grades: SI1 and SI2.
The diamond has overt inclusions; transparency and brilliance of that diamond could be influenced. Included diamonds can fall into three grades: I1, I2, and I3.
We often think of diamond carat size when speaking about jewelry. However, we shouldn't think of diamonds—or any gemstone, for that matter—in terms of carat size. Why? Because carats actually measure the weight of a gemstone. One carat, by today's criteria, is equivalent to one-fifth of a gram. Since different varieties of gemstones (such as a ruby and an emerald) have different densities, physical size alone cannot be used to compare carat weights across varieties. In fact, different varieties of gemstones may be close in size, but their carat weights could vary considerably. Under certain conditions, size can be used to compare carat weights. When comparing gemstones of the same variety with the same type of cut, size can be used to compare carat weight. A diamond carat size chart allows consumers to visually compare diamonds with the same diamond cuts according to carat size.
When it comes to a princess cut diamond ring or a cushion cut diamond ring with just one gemstone, carat weight is fairly straightforward. A single gemstone is expressed in terms of carat weight, but jewelry pieces often include multiple gemstones. In those cases, the individual carat weights can be added together and expressed as total carat weight (tw or ct tw).