Topaz

a precious stone. It is composed chiefly of aluminum, silicon, and fluorin. It has a glossy luster, but is almost as hard and as difficult to melt as a diamond. We cannot speak of a topaz color, for the gem may be colorless, or it may be of a straw-yellow, gray, greenish, bluish, or even reddish color. It is difficult to distinguish a colorless topaz from a diamond. Colored topazes are likely to fade on prolonged exposure to a strong light. The topaz occurs usually in the form of a crystal in such rocks as gneiss. Valuable gems are found in Maine, Connecticut, Colorado, Utah, and California, but chiefly in Mexico, Brazil, Japan, and Siberia. A topaz weighing 150 pounds in the rough was found near San Diego, California. It sold for $150. Cut and polished it produced a gem six inches in diameter, valued by experts at $10,000. See Gem