Cardassian rock wine is a drink of Cardassian origin. When it spoils, the rock wine becomes slightly magnetic.
Quark had several cases of Cardassian rock wine in his bar on Deep Space 9. Odo, investigating the possibilty of the dabo wheel being misaligned, thought it was unusual for Quark to sell Cardassian products, given that the majority of his customers were Bajoran. The cases were also stored near the dabo wheel, although Quark blamed Rom for storing them there. After Odo threatened to reveal the information to the general station populace, Quark had Rom move the cases of the Cardassian rock wine into storage. (DS9 novel: Space Camp)