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.
Africa Gems. Africa is best known as the leading source for diamonds, but the colored gemstone business has been growing rapidly in more than a half dozen different countries. Colored stone deposits are mainly in eastern and southern Africa, especially Kenya, Tanzania, Mozambique and Madagascar.hough Ethiopia is not known as a gemstone producer, a major find of high quality opal was discovered in Welo province in 2008. The prices on this fine opal have been very attractive and Ethiopian opal is now a strong competitor to Australian opal in the market.