Chinese vinegar is a dark complex vinegar made of glutinous rice and malt somewhat similar to a balsamic used in Chinese stir-frys, braises and sauces. Black vinegar is from the Chinkiang Province of China. This is a traditional ingredient in sharks fin soup.
You can find this vinegar in many Asian markets as well as online here at Amazon.com. Chinese Black Vinegar
Clearly the best thing to do is to find the black vinegar but if that's not practical then there are some options that will produce acceptable results; more so if you if you've never had the real ingredient to begin with:
glutinous rice, malt, water and salt