The oyster represents spiritual transformation. In nature it is almost unique because of its ability to transform a grain of sand into a pearl. It is this quality that tends to be brought to notice in dreams to demonstrate how we can change an irritant into something beautiful. We can spiritualize it. The oyster symbolizes our ability to make use of difficulty and negativity and create a new positive focus. In dealing with an irritant we are able to protect ourselves from further harm. Practically, the oyster is reputed to be an aphrodisiac food; in fact, this is because of its high zinc content, which affects the production of semen. For this reason a dream about oysters may be highlighting fertility issues. In dreams, as nowadays they can be expensive, they may well also represent the act of seduction. In a woman's dream oysters may signify seduction, but can also suggest sacrifice. Hypatia, an Alexandrian mathematician and philosopher, was flayed to death by Christians using oyster shells in 415 CE for her beliefs. In a man's dream, oysters themselves may symbolize his own sexuality. You might also like to consult the entries for Food, Sacrifices and Sand.