Turquoise Explained

Turquoise is a precious stone of beautiful blue through green color, capable of taking a high polish. It contains a large proportion of clay in its composition, and the color is due to the presence of copper. The turquoise has long been a favorite gem in the East, especially in Persia, where the finest specimens are found. Fine specimens also occur in the Sinai Peninsula and in New Mexico and other sections of the extreme southwestern part of the United States, where mines formally worked by the ancuent Mexicans have been discovered. When exposed to fatty acids, the turquoise loses its color and turns greenish. An imitation, known as bone turquoise, is easily distinguished, by examining it under a microscope, which reveals its structure. It is fossil bone colored blue by iron phosphate.