There are several different types of Opal including Boulder Opal, Fire Opal, Andean Opal (both Pink and Blue), Ethiopian Opal, Lemon Opal, etc. There are also differences in Common vs. Precious Opals. Each will have their own specific set of metaphysical properties and geological information. Opals are essentially silicon dioxide with water that has become trapped inside.
In general, Opal aids in strengthening personal and business relationships. It is often referred to as the stone of happy dreams and changes. Opal is a soothing stone, helping to balance mood swings and enhance trust in your own feelings. Opal awakens both psychic and mystical qualities. Opal can also release fear and send comforting support to those who are grieving.
On a physical level, Opal can help to improve the memory, ease the birthing process, cool a fever and fight infection.
Note: Because Opals contain water, do not leave them in sunlight or they will become brittle and break.