Opal is a hydrous, silicon dioxide. It is unlike other minerals because it is not crystalline. It is considered to be a hardened jelly.
The name opal derives from the Greek Opallos, meaning "to see a change (of color)." Opals range in color from milky white to black with flashes of yellow, orange, green, red, and blue.
The varieties of gem opal are as follows:
Healing properties - It was believed that water, fire and heat are enclosed in Opal so it is a remedy for many diseases. Opal helps against heart diseases, calms nerves, guards against melancholy, and improves vision.
Magical properties - It is a stone of deceptive hopes and illusions, secret passions, superstitions, the favorite stone of magicians and alchemists. Opals intensify intuition and promote inspiration. Opals help recollect the past lives.
Opal is the birthstone for the month of October. Element: Water.