1/Diamond Price Factors There are 8 basic price factors for diamonds Cut quality (Proportions, finish and light performance) Color Carat weight Cutting style & stone shape Clarity (Degree to which a stone is free from inclusions and blemishes) Creator (Man or nature?) Transparency (Degree to which a stone is clear, hazy or cloudy) Treatment status (Untreated or treated? What type of treatment?) Why the 4 Cs is No Longer an Adequate Pricing System If you've heard about the 4 Cs of color, cut, clarity and carat weight as a way to gauge diamond value, you may be surprised that there are twice as many factors to consider. The 4 Cs system of valuing gems is a clever, convenient way to explain gem pricing but it's limited in that it causes consumers to overlook the importance of cut quality, treatment status, transparency and source. The 4 Cs system was developed by GIA (Gemological Institute of America) in the 1950s. At that time, cloudy diamonds were considered industrial grade stones and were not set in jewelry, so transparency was not an issue. Neither was the treatment status because almost all diamonds were untreated. There were no separate price lists for rounds and other shapes. Therefore, it didn't matter that "cut" referred to both shape and the quality of the cut. The only lab-grown diamonds that were available were tiny stones that were used as industrial abrasives. The diamond industry has evolved and times have changed. High quality lab- grown diamonds have become widely available and sell for much less than natural diamonds. However, manmade diamonds are not always disclosed as such. Cloudy and hazy diamonds are often used in jewelry today, but their clarity grade on lab reports does not necessarily reflect their lower transparency and value. More and more diamonds are being treated to improve their color and apparent clarity grades; the price difference between treated and untreated diamonds can be significant so you should ask if the diamonds you're considering buying are treated. Even though treatments are supposed to be disclosed, not all sellers disclose them. Cutting style and shape are distinct price factors from cut quality and many gem labs now issue diamond reports with cut grades. In short, if you want to make accurate diamond price comparisons and get good buys, consider 6 Cs and 2 Ts instead of only 4 Cs. Price Factors Explained CUT QUALITY Cut quality, also called make, usually refers to the proportions and finish of a stone. These affect brilliance, which is defined by the American Gem Society (AGS) as "brightness with positive contrast effects." Brightness is the actual and/or perceived amount of light returned by a diamond. A brilliant diamond has a pleasing regular pattern of sharp, bright and dark areas. Cut quality assessment involves two fundamental considerations: 1.Do you see brilliance all across the diamond when it is face up? (fig. 1.1) Diamond brilliance should not be interrupted by large dark areas or white donut-shaped circular areas. (figs. 1.4 - 1.6) 2.Are you paying for excess weight that reduces the face-up size? (fig. 1.6) These are separate factors. A diamond can have high brilliance yet have bulky proportions that make it look small for its weight face up. Chapter 6 explains how to use the profile view of a diamond along with proportion measurements to help you determine if a diamond has unnecessary weight that makes it look small for its weight and it shows with photo examples some basic ways to judge brilliance from the face-up view. Evaluate diamond brilliance both with the naked eye and magnification using a diffused light source such as a fluorescent lamp with a translucent white cover. Cut quality is a crucial factor which can affect prices by as much as 50%. COLOR Basically, the less color the higher the price (except for fancy colors). D is the highest and most rare colorless grade. As the grades descend toward Z, color increases and the price decreases. See the GIA (Gemological Institute of America) color grading scale below, which was developed in the 1950s. Brown and gray diamonds are graded on the same scale. Each letter on the grading scale represents a narrow color range, not a specific point. A diamond is not poor quality just because it's yellowish. It's simply worth less because there's a higher demand and lower supply of natural colorless diamonds. Diamonds with a natural body color other than light yellow, light brown or light gray are called fancy color diamonds. These colored diamonds may cost a lot more than those that are colorless. For example, a one-carat natural pink diamond could sell for five to fifteen times more than a D color diamond of the same size and quality. Some diamonds are colored artificially by irradiation or high-pressure high-temperature treatments. They're worth significantly less than natural-color diamonds. In the GIA system, treated colored diamonds are not considered fancy diamonds. But in the trade, they're sometimes referred to as "treated (enhanced or processed) fancy diamonds." Chapter 5 has more details on color grading and fancy-color diamonds. CARAT WEIGHT In most cases, the higher the carat weight category, the greater the per-carat price of the diamond. A carat is a unit of weight equaling 1/5 of a gram. The weight of small diamonds is frequently expressed in points, with one point equaling 0.01 carat. There is a difference between the labels 1 ct TW (one carat total weight) and 1 ct (the weight of one stone). A ring with a 1 ct top quality diamond can be worth more than 10 times as much as a ring with 1 ct TW of diamonds of the same quality. When you price diamonds, think in terms of the per-carat cost. To calculate the per-carat cost of a diamond, use the equation: stone cost ÷ carat weight = per- carat cost of a stone. See Chapter 3 for additional information on carat weight. CUTTING STYLE & STONE SHAPE Shapes such as rounds cost more than others like pear shapes and squares. The effect of shape on price depends on the stone size, demand and available supply. Brilliant-cut square diamonds (princess cuts) may cost slightly more than step-cut squares, depending on size. They have the same shape but different faceting styles. Patented and trademarked cutting styles typically sell for more than generic cuts of the same shape. The most dramatic impact of stone shape and cutting style on price is with fancy color diamonds because their face-up color can be intensified by the shape and faceting style, and because the rough is so expensive. The price difference between some shapes can range from 10% to 100% depending on the diamonds and the dealer selling the stone. Chapter 4 shows and describes different cutting styles and shapes. CLARITY The fewer, smaller and less noticeable the inclusions and blemishes, the higher the price. There are 11 GIA clarity grades. They are summarized in the table below: Clarity grading is further discussed in Chapter 7. CREATOR Diamonds created by nature are called natural diamonds or mined diamonds. Diamonds created in a laboratory or factory are described as manmade, lab-grown, created or synthetic. As manmade diamonds have become more readily available, their prices have dropped significantly. Chapter 10 explains how lab-grown diamonds are made and tested and compares their benefits to those of natural diamonds. TRANSPARENCY The GIA and the book Gems by Robert Webster define transparency as the degree to which a gemstone transmits light. They list five categories of transparency: Transparent: objects seen through the gemstone look clear and distinct Semi-transparent: objects look slightly hazy or blurry through the stone Translucent: diamond is cloudy and milky like frosted glass Semi-translucent or semi-opaque: only a small fraction of light passes through the stone, mainly around the edges Opaque: virtually no light can pass through the gemstone Mineralogists use the term diaphaneity but gemologists prefer the term "transparency" because it's easier for lay people to understand. Not all diamonds are transparent. Some are cloudy or translucent because they have fine particles not individually visible at 10x magnification which interrupt the passage of light. Normally, the higher the transparency the more valuable the diamond. Even though transparency can have a significant impact on price, lab documents do not include it as a price factor. Gem labs, however, may take it into consideration when assigning a clarity grde. In addition, the comments section of lab reports may state "the clarity grade is based on clouds that are not shown." Some labs identify translucent diamonds as...
