The most valuable turquoise stones are bright blue with no spots or streaks; in other words, the color saturation and evenness drive the stone’s value. However, some stones have patterns that are attractive and desirable to some consumers. Turquoise that appears green (from impurities) is less valuable but retains some popularity due to its unique color. Stones with a yellow tone (from iron) are the least valuable. Turquoise prices vary depending on the quality of the stone.