The name turquoise, from the French expression Pierre tourques or Turkish stone, originated in the thirteenth century and describes one of the oldest known gemstones. Turquoise varies in color from greenish blue, through robin's egg-blue, to sky blue shades and its transparency ranges from translucent to opaque. Turquoise is plentiful and is available in a wide range of sizes. It is most often used for beads, cabochons, carvings, and inlays. Today the world's leading turquoise mines are in Arizona, New Mexico and Nevada, attributing to it's popularity in the American Southwest.