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Gem Quality
The 4C's
When shopping for a diamond or other precious gemstones there are certain primary things to consider. Called the 4 C's, these four standard criteria determine market value. They are Cut, Color, Clarity and Carat. Whether you are looking to invest, or buy that very special item, like a wedding ring, it is best to know what you are buying. Expensive stones are scored on all of these qualities, and may come with a laboratory Gemstone Cerificate.

More information:
More Facts on Gems
Books on Buying Gemstones
Diamonds & Jewelry for Sale