Xun, with a history of six to seven thousands years, is an earthen musical instrument, which can be categorized as a kind of ocarina. Its tamber similar to human voice, but emitting a very distant and primitive feeling, thus suitable for performing some lamenting aria.
There's a legend about Xun. Long time ago, there was a young man who had a fervant interest in Xun, and a beautiful lady named Huanghe (also the name for the Yellow River) heard his music and fell in love with him. But her father didn't like him because he was too poor. The young fellow missed the lady so much that he died of illness. His heart turned into a red diamond after his death. A craftsman passing by picked up the diamond and took it to the market for sale. The lady liked it very much and bought it. One day, the lady thought of the fellow when she was looking at the diamond and burst into tears. To her surprise, the heart broke into pieces when the tears fell upon it. So an old saying came into being -- The heart never dies until it sees Huanghe.
Check out some of the Xun tunes here.