opalescence watch

opalescence watch: this watch face is a macro photo of a lovely milky pearl coloured opal stone showing off stunningly brilliant fire and colour in its depths. The internal structure of precious opal makes it diffract light and depending on the conditions in which it formed, it can take on many colours. Precious opal ranges from clear through white, grey, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. It varies in optical density from opaque to semi-transparent. Opal is the national gemstone of Australia, which produces 97% of the world's supply. Opal is considered the birthstone for people born in October or under the sign of Scorpio and Libra. In the Middle Ages, opal was considered a stone that could provide great luck because it was believed to possess all the virtues of each gemstone whose colour was represented in the colour spectrum of the opal.