Learn about DIAMOND
Clarity - Cut - Color - Carat
The Diamond is the birthstone of April and the anniversary gemstone for the 10th and 60th years of marriage. Since diamonds are composed of a single element, they are the purest of all gemstones. Diamonds were discovered in India in 500 B.C., and the name "diamond" comes from the Greek word "Adamas" which means unconquerable - suggesting the eternity of love.
Since ancient Greece, diamonds and diamond jewelry have been the traditional symbol of love, and the ancients believed they were hardened dew drops, splinters from the stars or crystallized lightning. Today, the gem-grade diamonds are used to make fine jewelry and engagement rings. The industrial-grade diamonds are used mainly for cutting and polishing. A diamond is the hardest substance known to humankind, and is made of a crystallized carbon that has unique powers of light reflection.
Proportion refers to the angles and relative measurements of a polished diamond. More than any other feature, proportions determine a diamond's optical properties. Studies have shown that table size, crown angle, and pavilion depth have a dramatic effect on a diamond's appearance.
Symmetry is a grading term for the exactness of shape and placement of facets. Variations in symmetry include off-center culets and tables, poor facet alignment, misshapen facets, out-of-round girdles, and wavy girdles.
One of the first things most people learn about diamonds is that not all diamonds are created equal. In fact, every diamond is unique. Diamonds come in many sizes, shapes, colors, and with various internal characteristics.
All polished diamonds are valuable. That value is based on a combination of factors. Rarity is one of those factors. Diamonds with certain qualities are more rare—and more valuable—than diamonds that lack them.
Jewelry professionals use a systematic way to evaluate and discuss these factors. Otherwise, there would be no way to compare one diamond to another. And there would be no way to evaluate and discuss the qualities of an individual diamond. Diamond professionals use the grading system developed by GIA in the 1950s, which established the use of four important factors to describe and classify diamonds: Clarity, Color, Cut, and Carat Weight.
Few things in nature are absolutely perfect. This is as true of diamonds as anything else. Diamonds have internal features, called inclusions, and surface irregularities, called blemishes. Together, they’re called clarity characteristics. Clarity is the relative absence of inclusions and blemishes, Flawless diamonds are very rare—so rare, in fact, that it’s possible to spend a lifetime in the jewelry industry without ever seeing one, and they command top prices.
image 800 At the other end of the scale are diamonds with inclusions that can be easily seen by the unaided eye. Between the two extremes are diamonds with inclusions visible only under 10X magnification. Stones in the middle range make up the bulk of the retail market. There are 11 clarity grades in the GIA clarity grading system. They are Flawless, Internally Flawless, two categories of Very, Very Slightly Included, two categories of Slightly Included, and three categories of Included. The effect of a clarity characteristic on the clarity grade is based on its size, number, position, nature, and color or relief.
Occasionally, if an inclusion has the potential to cause damage to a stone, it can affect the grade. But this is rare, and usually applies only to Included (“I”) diamonds. Diamond professionals use a set of terms that originally included very very slightly imperfect, very slightly imperfect, slightly imperfect, and imperfect. In recent years, the term imperfect has been replaced with included. (GIA uses included in its clarity grading system.) These terms were shortened to the initials VVS, VS, SI, and I. The abbreviations eventually gained acceptance throughout the international diamond community. Their use is now widespread regardless of how the words they stand for translate into various languages. Very may translate to tres in French, for instance, but in France a very slightly included diamond is still a VS. Even a country like Russia, with a completely different alphabet, uses the same abbreviations.
A beautifully finished diamond is dazzling, with every facet displaying the craftsman’s skill and care. When a diamond interacts with light, every angle and every facet affects the amount of light returned to the eye. This is what gives it its face-up appearance.
A beautiful diamond looks the way it does because of three optical effects: white light reflections called brightness, flashes of color called fire, and areas of light and dark called scintillation. Pattern is the relative size, arrangement, and contrast of bright and dark areas that result from a diamond’s internal and external reflections. There must be enough contrast between the bright and dark areas to give the pattern a crisp, sharp look. The diamond industry has long known that some proportion combinations make light perform better than others. In recent years, however, scientists and researchers in GIA’s Research Department and the GIA Laboratory have shown that there are many variations and combinations of proportions that will maximize brilliance and fire in round brilliant cut diamonds.
The term “cut” also can describe a fashioned diamond’s shape. Shapes other than the standard round brilliant are called fancy cuts. They’re sometimes called fancy shapes or fancies. Fancy shapes also have names of their own, based on their shapes. The best known are the marquise, princess, pear, oval, heart, and emerald cut.
Diamonds come in many colors. Diamonds that range from colorless to light yellow and brown fall within the normal color range. Within that range, colorless diamonds are the most rare, so they’re the most valuable. They set the standard for grading and pricing other diamonds in the normal color range. The GIA D-to-Z scale is the industry standard for color-grading diamonds. Each letter represents a range of color based on a diamond's tone and saturation.
Many diamonds emit a visible light called fluorescence when they’re exposed to ultraviolet (UV) radiation. Although invisible to the human eye, UV radiation is everywhere. Sunlight contains it. Fluorescent lights emit it, too. Under the right conditions, you can see fluorescence in about 35 percent of gem diamonds. Blue is the most common fluorescent color in gem-quality diamonds. In rare instances, fluorescence can be white, yellow, orange, or many other colors. Strong blue fluorescence can make a light yellow diamond look closer to colorless in sunlight. Blue and yellow are color opposites and tend to cancel each other out, so blue fluorescence masks the yellow color. If the fluorescence is too strong it can make the stone look cloudy or “oily,” which can lower the value of the diamond.
Many goods are sold by weight—by the kilogram, ounce, pound, or ton. Even people who have never bought a diamond are used to the idea that weight and price are related. They understand that a larger diamond is probably more valuable than a smaller one. But there are two things that often surprise people when they start learning about diamonds and carat weight. The first is the precision with which diamonds are weighed. Diamond weights are stated in metric carats, abbreviated “ct.” One metric carat is two-tenths (0.2) of a gram—just over seven thousandths (0.007) of an ounce. One ounce contains almost 142 carats. A small paper clip weighs about a carat. The metric carat is divided into 100 points. A point is one hundredth of a carat.
Diamonds are weighed to a thousandth (0.001) of a carat and then rounded to the nearest hundredth, or point. Fractions of a carat can mean price differences of hundreds—even thousands—of dollars, depending on diamond quality. Over a carat, diamond weights are usually expressed in carats and decimals. A 1.03-carat stone, for example, would be described as “one point oh three carats,” or “one oh three.” Weights for diamonds that weigh under a carat are usually stated in points. A diamond that weighs 0.83 carat is said to weigh “eighty-three points,” or called an “eighty-three pointer.”