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.
Coober Pedy produces the bulk of the world's white opal. The opal mining fields of Coober Pedy lie in the outback of South Australia, Stuart Range, 750 km north of Adelaide. Many of the locals in Coober Pedy prefer to live underground in dugouts where it is cool in summer and warm in winter.