Concept in Definition ABC

This semi-precious stone does not have a crystalline structure, but it does have a wide range of shades. It's about a mineral amorphous colloidal that is made up of tiny crystals and is normally found in the form of streaks of different colors.

Main features

Opal contains silicon and oxygen in a proportion equal to quartz, so they can sometimes be confused.

When studied microscopically, it has been seen that it is made up of tiny spheres of silica that are surrounded by empty spaces. It is a little less hard than quartz (its hardness reaches six points out of ten in the scale Mohs), it does not scratch easily and is quite fragile due to the fact that there may be Water without crystallizing.

There are two main varieties: noble and common opal

While both are used as gemstones, only the noble produces the iridescence of the colors of the rainbow. Its varied colors are due to diffusion and reflection of light from the tiny transparent silicon spheres. The noble opal's color varies greatly, but the most abundant are white, gray, brown, orange, and blue.

In Australia you can find the most appreciated opal (black opal) and in Mexico you can find the so-called fire opal.

Its historical and symbolic dimension

The Greeks of the ancient world associated the beauty of this stone with the idea of ​​glory and social prestige and the wealthy Romans gave them to their wives and lovers. In the Catholic Church it was highly valued and, in fact, the bishops used it for their rings as a symbol good luck.

Throughout history, opal has been associated with Health and wealth. It is also said that it is a karmic stone and that it contributes Justice and harmony. In the eastern world it is valued as a sacred gem linked to fidelity and good fortune.

In the context of astrology it is considered to be a protective element associated with the sign of Libra and during the Middle Ages it was believed that with it it was possible for people to become invisible. For the ancient Arabs it was a stone fallen from heaven and the Native Americans used it to attract visions and allow divination.

In the medicine Ayurvedic the different colors of opal are associated with health. Thus, the stones of red color fight throat problems and help overcome depression and those of black color improve sexual appetite.

Photos: Fotolia - Rafael Ben-Ari / Vvoe