Chinese Faux jade

In almost all dictionaries, the Chinese character 'yù' is translated into English as 'jade'. However, this frequently leads to misunderstanding: Chinese, Koreans, and Westerners alike generally fail to appreciate that the cultural concept of 'jade' is considerably broader in China and Korea than in the West. A more accurate translation for this character on its own would be 'precious/ornamental rock'. It is seldom, if ever, used on its own to denote 'true' jade in Mandarin Chinese; for example, one would normally refer to 'ying yu' ( 'hard jade') for jadeite, or 'ruan yu' ( 'soft jade') for nephrite. The Chinese names for many ornamental non-jade rocks also incorporate the character 'yù', and it is widely understood by native speakers that such stones are not, in fact, true precious nephrite or jadeite. Even so, for commercial reasons, the names of such stones may well still be translated into English as 'jade', and this practice continues to confuse the unwary.

From:chinese-jewelry-and-jade.blogspot.com