Moss Opal

  Moss Opal

 Opal, hydrous silicon dioxide, is a non-crystalline form of quartz containing up to 30 percent water. There are many types of opal. The name Opal comes from the Sanskrit upala, meaning “valuable stone.” The common opal is milky white, but opals can run the gamut from greenish-yellow to brick red. There are some special varieties such as the fire opal of Mexico with rich reds and purples and the black opal of Australia, but there are many others besides. Some are cachalong, common (potch), boulder, girasol, harlequin, hyalite, hydrophane, ironstone, liver, moss, peacock, wood, white, and water. Unlike other opals, common or potch opal is a colorless opal produced by spheres which are not stacked orderly. Other opals have orderly stacked spheres which produce the play of colors characteristic of opals.