What You Need to Know about Opals
The opal is an amorphous form of silica composed of 6 to 10 percent of water, but the water content can be as high as 21 percent. It can occur in fissures of any kind of rock and is more commonly found among limonite, marl, basalt and sandstone rocks. Approximately 97 percent of the worlds opals production comes from Australia and it has been named the Australian national gemstone.
Opal has an internal structure that causes it to diffract light. Depending [...]
June 5th, 2011 by hendri 













