Jade is the name used to embrace a variety of colored stones, the most valuable of which are the silicates called nephrite and jadeite. Jadeite came from Burma. The main source of Chinese nephrite was the north-western province of Xinjiang, where jade was found as boulders in river beds, and was also mined. Jade is too hard to carve, so abrasive sands are used with grinding and cutting tools to wear away the stone. Chinese jades come in many colors, the most common of which are green and white. The sixteenth-century cup shown at the front is made from nephrite jade.