By Mitch Endick
 Diamonds almost always have defects and one of the main defects is carbon spots. Their influence upon diamond value has to be taken into account along with the influence of color. A stone may have great color, yet may yield some carbon imperfections making it far less valuable than an off color stone.
A truly colorless diamond is very rare, so it may be stated that one perfect in crystallization is also seldom. A perfect crystal is rarely found in nature. The diamond cutter tries to remove as many of these imperfections as possible, without cutting the weight of the actual stone. Usually after the stones are cut most of them still have some imperfections and blemishes.
One of the most common types of imperfection is known in the trade as carbon or as carbon spots. Diamonds are one of the many types of carbon. Graphite is a second variety, and amorphous carbon such as charcoal, lampblack is a third.
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By Victor Epand
 Want to know if you've got the real thing? Rub the strand across the front of your upper teeth. It may sound strange, but real pearls will feel rough or gritty while fake ones will feel smooth. This is due to the micropores found on the genuine article.
Imitation pearls are usually made by dipping a glass or plastic bead into a solution of fish scales. The coating is generally fairly thin and will chip over time. Check the pearls for tiny chips or flakes near the hole drilled through them. If you see chips, chances are your pearls are fake.
Try holding the pearls in your hand for a minute. Real pearls will feel cold initially, then will warm.
Real pearls can be either natural or cultured. Natural pearls are formed when a mollusk secretes a substance called nacre to coat an irritant that makes its way inside the animal's shell. Cultured pearls are formed with a little human help -- an irritant is purposely introduced into the shell of the animal. You usually need an x-ray or an expert |
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