Opal is a hydrous, silicon dioxide. It is unlike other minerals because it is not crystalline. It is considered to be a hardened jelly. It's water content sometimes being as high as 20% but is usually between three and ten percent.
Opal is a mineraloid gel which is deposited at relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, and basalt. It is a unique gemstone with a beautiful play-of-color display. It can exhibit a full range of hues from the color wheel set against a light or dark background. The color of Opal ranges from clear through white, gray, red, yellow, green, shore, blue, magenta, brown, and black.
Precious opals are translucent to transparent and are distinguished by a combination of milky to pearly opalescence and an attractive play of many colors. These colors flash and change as a stone is viewed from different directions are caused by interference of light along minute cracks and other internal inhomogeneities.
Black opal is regarded as an extremely lucky stone. In ancient times opal was accepted as a symbol of faithfulness and confidence and has been described in medival times as a cure for diseases of the eye. Opal along with tourmaline are birthstones of a person born under the zodiac sign of Libra (Balance) from Sept. 23 - Oct. 23. It is also the anniversary gemstone for the 14th and 18th years of marriage.
0 comentarios:
Post a Comment