robert brown associates coorparoo d c qld australia (1 results)

Trade paperback. Special Collectors' Edition. 80, [4] pages. Illustrations (many in color). Map On July 28, 1993 the opal was proclaimed by the Australian National Government as Australia's national gemstone. Excerpts from an on-line posting: "For artist, historian, novelist and opal miner Len Cram the ability to capture this moment was a long process and one he still strives to create. Creating non-commercial opals synthetically in his tin shed has raised eyebrows for geologists but for Len it was journey of discovery in learning everything there is to know about his life s passion; opals. Studying them for over 60 years and sharing his research and knowledge on the topic through over 25 books.Len seems to see it less about passion and more about preserving and capturing the illustrious history of Australia s national gemstone. Although aware of the knowledge that he holds, Len reiterates that he s not trying to boast but at its core he was trying to create a well of knowledge for future generations to draw from. "I suppose for a lot of people it s not important but to me it was and a lot of it s gone. A lot of those people are dead but I ve got them all on audio tape. I interviewed over 100 people from all the opal mines across Australia and got their stories and now a lot of them are gone. From Wikipedia: "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. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Opal is the national gemstone of Australia. Australian opal has often been cited as accounting for 95-97% of the world's supply of precious opal, with the state of South Australia accounting for 80% of the world's supply. The internal structure of precious opal makes it diffract light; depending on the conditions in which it formed, it can take on many colors. Precious opal ranges from clear through white, gray, red, orange, yellow, green, blue, magenta, rose, pink, slate, olive, brown, and black. Of these hues, the reds against black are the most rare, whereas white and greens are the most common. It varies in optical density from opaque to semitransparent." Very good. Signed by author. Signed and dated on half-title.