With the new year upon us, we thought it would be a good time to review some gemstones basics, starting with one of the most beloved of all gems, the diamond.
Diamonds are crystals made of pure carbon, and are the only gemstone composed of just one element. Small amounts of other elements might be in diamonds as impurities, and often give diamond its color variation.
Diamonds are formed under crushing pressures and intense heat, mostly in the Earth’s mantle and delivered to the surface by deep-source volcanic eruptions. These eruptions produce the kimberlite and lamproite pipes that are sought after by diamond prospectors.
Diamonds have a hardness of 10 on the Mohs Scale. For millennia, diamonds have been thought to be the hardest material in nature. But in 2009, a composite material containing the mineral wurtzite boron nitride (w-BN) was shown to have the same resistance to indentation as diamond. In fact, research in China and the U.S. suggests that pure w-BN is significantly harder than diamond.
About 2,500 years ago, diamonds were first discovered in India. While the U.S. is the largest consumer of diamonds, there is barely any production here. The only mine is a state park called the Crater of Diamonds State Park in Arkansas where tourists can pay a fee to look for diamonds. The park yields just a few hundred carats per year.
The Four Cs
In the ‘40s and ’50s, the Gemological Institute of America (GIA), an educational and research non-profit organization founded in 1931, developed the “4Cs” and the GIA International Diamond Grading System™ to objectively compare and evaluate diamonds. Today, even if you buy or sell a diamond in another part of the world, the jeweler will likely use the same GIA grading systems. The 4 Cs are:
- Color: Most diamonds run from colorless to near-colorless, with slight hints of yellow or brown. “Color” is not how much color a diamond has, but the degree to which it is colorless. The GIA set the industry standard with its D-Z scale (D is colorless while Z means the diamond has the most yellow.) The exception to this rule are fancy colored diamonds which aren’t included in the GIA’s D-Z scale. Colors beyond the Z color are considered fancy colored diamonds.
- Clarity: Most diamonds have tiny crystals, feathers, or clouds within them, called “inclusions.” Surface imperfections are called “blemishes.” The rarest diamonds are flawless and have no internal inclusions or external blemishes. The GIA uses a Clarity Scale of 11 grades that are measured using 10X magnifications.
- Carat: Signifies the weight—not the size—of the diamond. One carat is equal to 200 milligrams. Since heavier diamonds are rarer than smaller diamonds, the value is higher the heavier the carat weight.
- Cut: The cut of a diamond refers to its proportions, symmetry, and polish. When evaluating cut, two aspects are assessed: shape (round, marquise, square cut, etc.), and how well the cutting was executed. It must be geometrically precise, since it will affect a diamond’s fire (the flash of rainbow colors from within) and brilliance (its sparkle). The cut was historically the most subjective and difficult to standardize during appraisal, but due to advances in technology, the GIA introduced its cut grading system in 2005.
Fancy Colored Diamonds
Not all diamonds fall into the typical white-yellow-brown color range. They can be pink, blue, purple, red, orange, or any color. Colored diamonds, known as authentic fancy colored diamonds, get their color from the trace elements they are exposed to. For example, radiation can create a greenish tint, while large amounts of nitrogen causes a yellowish color. Real natural fancy colored diamonds are very rare and expensive, but through irradiation and heat treating, gemologists are able to enhance the color of most natural diamonds. Fancy colored diamonds are found in 12 different colors, with more than 90 secondary hues and nine intensity levels within the 234 color combinations.
Fancy colored diamonds are graded a bit differently than white diamonds. The four main criteria for determining a fancy colored diamond’s value are hue, color saturation, color purity, and availability. The more rare a diamond is in color, the more valuable it will be. If the color is richer or saturated, the diamond will also be worth more. And like a white diamond, a colored diamond’s clarity or purity of the color will also increase its value. Also, inclusions can be desirable. Inclusions are actually flaws, but in a colored diamond, they can create unique tones and beautiful flashes of color.
People have been able to manufacture diamonds since the 1950s. These are known as synthetic diamonds. Today, more than 100 tons of diamonds are manufactured every year. Most of these diamonds are used to make cutting tools and abrasives. Synthetic diamonds are often undistinguishable from naturally occurring diamonds, but they can be identified by laboratory tests.
For diamonds not in a metal setting, gently clean the diamond with a solution of ammonia and water. For diamonds in metal settings, soak the piece in a solution of warm water and mild detergent for two to five minutes. Gently scrub the diamond with a soft toothbrush or jewelry brush. Then, rinse the diamond in warm water to remove remaining detergent. Buff the diamond dry with your cloth.
Whether you’re getting engaged or just looking to buy beautiful, quality diamond jewelry, Adina by Empire Jewelers has a magnificent collection of estate and vintage diamond jewelry, available at true wholesale prices, as well as a wide variety of precious and semi-precious gemstone and gold jewelry. Shop online today, and remember, if you have any questions, please don’t hesitate to contact us.