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.
The Olympic Australis Opal is believed to be the largest gem opal ever found.   Found in 1956 at the Eight Mile opal field in Coober Pedy, South Australia, it was found a â¦ t a depth of 30 feet and so named because the Olympic Games were being held in Melbourne at the time.