How does turquoise jewelry get its color?

Turquoise is formed when water percolates through a rock containing aluminum and copper, and therefore is found around copper deposits in arid or semi-arid environments. The bluish tints of turquoise are caused by idiochromatic copper, while iron impurities and dehydration give the stones a greener hue.

Turquoise forms as a conglomerate of micro crystals with flecks and color variations throughout. The more tightly packed the crystals, the less porous and more durable the stone is. Jewelers often treat lower-quality turquoise with resin to improve its luster and prevent fading. Light blue turquoise is the most common color for jewelry, but turquoise also comes in shades of blue-green, green and coppery-red.