Opal is a silica based material with a very high water content. Material is graded according to clarity, depth of colour, proportion of impurities and quality of finish. Opals with fire (BLACK and FIRE OPAL) spark because the light refracts off the minute silica particles, which have an irregular structure. To keep opals happy do not let them sit in the sun or dry out, as this may lead to cracking, crazing or dulling.
Most opals are feminine and watery in their nature, yet is would be a mistake to see them as gentle or soft! Their watery nature makes them all generally useful at dealing with emotional conditions, or in drawing out deep or long-held restrictive and paralysing beliefs about one's Self. They are the "tears of the Earth" and, like tears, help us to confront and release things that may prevent forward progress, or that have built up within to such a level that this has resulted in physical disease or discomfort. The common opals are gentler in their approach than the precious opals, but these too (through the intensity of the full-spectrum of Light they can hold and channel) have huge potential for confrontation with, release, and subsequent clearance of, anything that does not truly serve us and our life purpose. The newer transparent / opaque opals have come now to awaken us to the full expression of who we are, and to the reality and possibility of joy in our lives. NB: You can read more uder the section for each individula Opal type - e.g. see FIRE OPAL under F; VIOLET OPAL under V etc.