Although evaluating gemstones shall always be done by experienced jewelers, buyers shall be aware of the basics even before asking for expert assistance to prequalify stones they like in order to limit the scope of the evaluation and save costs.
The 4 Cs of diamonds and gemstones, standing for cut, color, clarity, and carat weight, are the key characteristics, initially outlined by the Gemological Institute of America (GIA) as a part of their diamond grading system. Today, the 4 Cs concept is applied to all gemstones, helping experts and buyers determine gemstone quality and value.
For diamonds, the less color they have, the higher is the price. While colorless diamonds do exist, they are quite rare. Most of the diamonds do have color, measured on the scale from D to Z, with everything after Z classified as colored diamonds.
Meanwhile, the colored or fancy color diamonds, having intense or rare colors, are more rare and are valued at much higher prices which can reach over $100,000 per carat. Even though the trend for colored diamonds has started only about two decades ago, they demonstrate a high increase in value and are considered a great investment.
For other gemstones, such as emeralds, rubies, or sapphires, the more color they have, the higher they are valued. Their color is further characterized by hue, tone, and saturation.
The hue is what we immediately see when looking at a stone, describing it as red, yellow, blue, or anything. More scientifically speaking, it is the position of any color at the color spectrum on a color wheel. The tone is about lightness or darkness, while saturation is the degree of intensity. Some stones, such as Columbian emeralds or Burmese rubies, are valued primarily for their vivid and saturated colors.
The clarity factor measures inclusions in stones, which are avoided for some and are expected for others. In the case of diamonds, clarity is evaluated under a 10x microscope and has six grades, starting from Flawless (FL) and Internally Flawless (IF), ranging through VVS and VS stones, and ending with so-called Included (I1-I3) stones, which have visually noticeable inclusions. Still, despite its seeming importance, clarity is the least critical factor for diamonds, according to some buyers, as long as the stones are eye-clean, as, for example, VS2 stones.
Other gems have their own clarity standards and are classified into three types, starting from those with none or very few inclusions, such as aquamarine, and ending with stones, which most often have inclusions, like emeralds. The grading systems would also be different for various types of stones as, for example, rubies are supposed to have lots of inclusions, which, meanwhile, should not reduce their brilliance. At the same time, top quality emeralds should have inclusions at a minimum.
Often associated with shape, the cut measures how gemstones reflect light and is more related to proportions, faceting, and symmetry than the shape. In determining the price, a shape of a stone, such as an oval, cushion, square, marquise, or anything else, is much less important than proportions that matter most.
For diamonds, the cut is considered the most crucial of all 4 Cs as it influences stones’ brilliance and ability to sparkle, throwing off flashes of color. An ideal cut should not be too shallow or too deep and must allow the stone to reflect as much light as possible. Although diamonds are faceted in various ways, the best reflection is achieved with round brilliant shape, which we often see with this type of stone.
For other gems, cut and shape are less important than clarity and color. Still, the beauty of a gemstone can be revealed only with a quality cut and finish, which help minimize inclusions and improve the perception of color. The choice of shape is up to jewelers and customers, but some shapes, such as an emerald cut, bearing the name of the stones it’s associated with, can work better with one type of gems than with others.
The carat is the weight of the gemstone, equal to 0.2 grams. As large, high-quality gems are less common, the price per carat goes exponentially with the size.
As can be seen from above, the weight of gemstones in carats is just one of the factors affecting the price, so two stones of the same carat with different colors, cut, or clarity can stay at opposite ends of the price spectrum. However, with the remaining Cs being equal, a higher weight in carats is what makes a stone truly unique.
Summing It Up
4 Cs of diamonds and gemstones are not only buzzwords in the world of luxury and affluence but also essential tools that help to understand the market and make the best purchase for your budget. They help to see the difference in the tiniest stone and realize the logic behind the prices.
In this respect, keeping in mind the desired 4Cs for your gemstones is vital for going through the inventory and spotting an opportunity. Given the importance of these characteristics, we are going to go into further details of 4Cs for each individual type of gemstones in our next articles.