Aquamarine is another of the gems composed of Beryl. It
occurs in colors of light sky blue, greenish blue, or greenish yellow.
The light sky-blue stone is the one of the most value, and is very
brilliant, especially by artificial light. Recently aquamarines have
become more and more popular, and this is doubtless due to the
discovery of many fine masses of the crystal. Some of the finest of
these are in Siberia, India, Brazil, and in many different localities
in the United States, notably in North Carolina. The color of the
aquamarine may be altered by various artificial means, and experiments
along this line have been undertaken for many years by some of the
German universities, resulting in the discovery of a method by which in
rare cases the less valuable greenish-blue variety may be changed to a
shade of light sky blue of great value without altering the stone to
any perceptible degree. Because of this, it is thought that the
coloring matter in the gem must be organic.