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Emeralds are the May birthstone, and have long been associated with spring and enduring love. The emerald is a form of the beryl stone, and it is green because of the chromium in the crystal matrix. The value of an emerald can range from only a few dollars for an opaque emerald, which is cloudy and might have only a light green color, to a very clear emerald, which can fetch more money than a diamond.

How Emeralds Form

Emeralds form when chromium comes into contact with beryl, aluminum and silicon through volcanic eruptions, earthquakes and erosion of the topsoil. Opaque emeralds have a large proportion of other elements trapped in the crystal matrix, which makes them appear cloudy. Emeralds take millions of years to form. The oldest emeralds are in Zimbabwe, and these are 2,600 million years old. Emeralds are found in various locations worldwide, but the majority of them are located in Brazil, Columbia, Zimbabwe and Pakistan.

Quality of Emeralds

The quality of an emerald is determined by its color and its clarity. Most emeralds have some flaws, called inclusions, because emeralds break easily under pressure. These do not greatly affect the value unless they cause the emerald to become opaque, in which case they are not considered to be gem quality. When emeralds are flawless, they are among the most valuable gemstones.

Uses for Opaque Emeralds

Opaque emeralds are not considered to be suitable for fine jewelry, but they are used in less expensive jewelry or made into beads. Opaque emeralds, when used as beads or pendants, have an appearance similar to green turquoise with its mottled appearance. Low-quality emeralds are also used for industrial purposes such as grinding stones or as pivots for spindles.

Where to Purchase Opaque Emeralds

Opaque emeralds can be found at many jewelry stores that specialize in both fine jewelry and semiprecious stones. The largest variety of opaque emerald jewelry and loose opaque emeralds can be found on online auction sites. In addition to these sources, some online retailers sell cut opaque emeralds that can be set according to your specifications.