Turquoise is composed of aluminium phosphate and copper. Its name originates from the French word for Turkish stone, as in ancient days it was transported through Turkey. It was very popular in Ancient Egypt and Ancient Persia, and known to man since at least 6,000 BC. Delicate veining, caused by impurities is desired by some collectors as proof of a natural stone. Turquoise is found in Iran, southwestern United States, Africa, Australia, Tibet, China, Siberia and Europe. Source: Encyclopedia of gemstones and minerals.