The corresponding Chinese word yu was not been generally accepted. In 1863 a Frenchman proved that two minerals were considered to be the same stone, a gemstone which had been known as 7000 years. He named one jadeite and the other nephrite. In the trade, numerous green opaque stones have been falsely offered under the name “jade”. Differentiation between jadeite and nephrite is very difficult, and this may be the reason why the word jade is used as a description of both.
In pre-historic times, jade was used in all parts of the world for arms and instruments, because of its exceptional roughness. Therefore nephrite is sometimes called “axe-stone”. For over 2500 years, jade was part of the religious cult in China and mystic figures and other symbols were carved from it. In pre-Columbian Central America, jade was more highly valued than gold. With Spanish conquest, the high art of jade carving in America came to a sudden end. In China however, this art never interrupted. In former times only nephrite was worked in China, but the last 150 years jadeite imported from Burma has also been used.

*Info by Walter Schumann “Gemstones of the World”