Some colors are unique to one mineral. Jadeite is harder than nephrite. Both nephrite and jadeite are too hard to be inscribed using metal tools. They must be ground with a medium containing a harder substance, such as diamond or quartz powder mixed with water. When worked and polished, the fine luster of polished nephrite appears oily and is described as the shining of oil .
Polished jadeite is described as the shining of glass .
Due to the labor intensity of jade carving in ancient China, the limitation of raw material to certain regions, and its association with the virtues of good men in Confucianism, jade was considered to be more precious than gold in China.