Opal is a stone of inspiration which enhances imagination and creativity. It helps one release inhibitions and enhances memory. Opal is also a very spiritual stone, and can help one be "invisible" in situations where they don't care to be noticed.
Opal brings happy dreams. It also eases the process of change. Physically, opal is helpful for eyesight and Parkinson's disease. The opal is both projective and receptive. The opal contains the colors as well as the qualities of many, many other stones.
The ancients used it to promote astral projection. They can also be used to recall past incarnations. Opals are worn to bring out ones inner beauty.