Bluxdsjewelry

  A poem Opal is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Due to its amorphous property, it is classified as a mineraloid, unlike crystalline forms of silica, which are considered minerals.    A blue fire opal ring.  It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt.    Opals The name opal is believed to be derived from the Sanskrit word upala (उपल), which means 'jewel', and later the Greek derivative opállios (ὀπάλλιος), which means 'to see a change in color'.    White Opals There are two broad classes of opal: precious and common. Precious opal displays play-of-color (iridescence); common opal does not.[5] Play-of-color is defined as "a pseudo chromatic optical effect resu...