Saturday, May 29, 2010
Why are natural emeralds so rare in occurrence compared to beryl and aquamarine, which are the same mineral but a different color?
Why are beryls and aquamarines found in pegmatite deposits but rarely so are emeralds? If you are a prospector of gemstones and of emeralds you should know the reason before venturing forth.
To understand the occurrence of emerald and beryl in general you have to study the chemical composition of the mineral beryl and what causes the color. Beryl is a beryllium aluminum silicate which if it had no coloring impurities would naturally be colorless, and many are, such as the colorless gem beryl called “goshenite”. These crystals may have lots of alkali ions and water molecule impurities but these don’t cause any color.
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