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Seven qualities that make a diamond valuable

While an estimated $13 billion of rough diamonds are produced each year, only 30% of those are of gem quality, meaning they are good enough to be distributed to experts for cutting, polishing, and jewelry manufacturing. Of those, only a fraction are truly investment worthy.

If you are planning to purchase a diamond or diamond jewelry for Mother's Day or other special occasions, you may want to learn what makes them valuable, so that you can make an educated choice. After all, diamonds are forever.

How are diamonds formed?

Real diamonds are the hardest natural occurring substance in the world. They are made up of tightly bonded carbon which are literally stuck together forever, thanks to the extreme heat and pressure in which they're formed, 90 to 120 miles below the Earth's surface. Approximately 65% are found in Africa, though they are found in many other countries around the world today as well.

What makes a diamond valuable?

Jewelry professionals use a systematic approach that was developed in the 1950s to evaluate and grade diamonds. We've listed the four most important factors used (known as the four Cs: color, clarity, cut, and carat), as well as a few extras that are good to know:

Diamonds can vary dramatically or subtly in color. However, even a slight color difference can affect its value significantly. Diamonds range from GIA grade D, which is colorless, up the alphabet to light yellow and brown, at GIA grade Z. Colorless diamonds are the rarest and therefore the most valuable.

About 35% of diamonds emit a visible light, called fluorescence, when exposed to ultraviolet (UV) radiation. It is typically blue but can be other colors as well. Too much fluorescence can cause the gem to look cloudy or "oily", therefore lowering its value.

Diamonds have internal features, called inclusions, and surface irregularities, called blemishes, that can lower their value. However, inclusions (which are inside the diamond) are helpful in separating diamonds from imitations and can help a gemologist identify individual stones, since no two are exactly the same. The GIA clarity scale ranges from Flawless to I3 (included).

A diamond's proportions determine how light performs when it enters the diamond. Therefore, the skill with which it is cut can make the difference between a high-quality diamond and one of lower quality. As a general rule, the higher the grade cut, the brighter the diamond. The cut can also refer to the shape of the diamond: marquise, princess, oval, heart, and emerald cut.

Carat weight
Diamonds weights are stated in metric carats (ct). One metric carat is .2 of a gram, just over .007 of an ounce. One ounce contains 142 carats. The metric carat is divided into 100 points, each of which is one hundredth of a carat. The larger the carat, the more valuable the diamond; however, the relationship is not equal. In other words, a 1-carat diamond will not be worth half of a 2-carat diamond. The larger diamonds are worth much more.

Diamonds can be enhanced for color, to make it colorless or change its color, or for clarity, to fill in fractures or drill out inclusions. While these treatments can make a diamond look better, they may not always increase its value.

How it was formed

Not all diamonds are real. Some are synthetic, meaning they have essentially the same chemical composition, crystal structure, optical, and physical properties of diamonds found in nature, but were made by man and not formed in nature. Others are simulants, such as cubic zirconia, which are unrelated to diamonds at the atomic level. Obviously, real diamonds, formed in the earth, are the most valuable.

The more valuable the diamond, the more protection you need

Make sure that you get a quality appraisal to see how valuable your diamond actually is, then insure it for its full value, so that if something happens to it, you'll be able to repair or replace it. Note that most homeowner's insurance may limit your coverage for jewelry, including diamonds, so you may want to look into separate Valuable Articles coverage.


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