OPAL GemShoppy March 24, 2015 Gemstones Opal is given as a symbol of hope, happiness and truth. Opal is fundamentally colourless, but such material is rarely found. Disseminated impurities generally impart to opal various dull body colours that range from the yellows and reds derived from iron oxides to black from manganese oxides & organic carbon. The milkiness of many white & grey opals is attributable to an abundance of tiny gas-filled cavities in them. Precious opal reflects light with a play of brilliant colours across the visible spectrum, red being the most valued. Amorphous silica, SiO2 + nH2O, A solidified jelly so it has no crystal structure and contains up to 13% water. Precious opals are translucent to transparent and are distinguished by a combination of milky to pearly opalescence and an attractive play of many colours. These colours flash and change as a stone is viewed from different directions are caused by interference of light along minute cracks and other internal inhomogeneities. Opal is extensively used as a gemstone. Various forms of common opal are widely mined for use as abrasives, insulation media, fillers, and ceramic ingredients. The name’s origin: The name opal is derived from the Latin word opalus, meaning seeing jewel. According to another theory the word opal comes from upala, a Sanskrit word simply meaning a stone. Opal along with tourmaline are birthstones of Libra (Balance): Sept. 23 – Oct. 23.