Notable locations in Williamsburg: Williamsburg Sport Complex (A), Sport Hill Country Club (B), Iowa County Ambulance Williamsburg (C), Williamsburg First Responders (D), Williamsburg Public Library (E), Williamsburg Police Department (F), Williamsburg Fire Department (G). Display/hide their locations on the map.
Types of Opal. Opal is a hydrated amorphous form of silica; its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike the other crystalline forms of silica, which are classed as minerals.
In addition to Australia, Opal is also found in Brazil, Guatemala, Honduras, Mexico and even the US, China and Japan, and in Europe Hungary which may have been the origin of the earliest examples of opal jewelry. What opal is and how it is formed. Types of opal. Australia's opal fields. How to choose an opal. Patterns. Value. Caring for your opal. Opal is the gemstone intimately connected with Australia, and rightly so, as more than 95% of the world's opal is mined there.