A Field Guide to Australian Opals by Barrie O’Leary ( Signed Copy)

From the cover: “Australian opals are the most beautiful and sought-after multicoloured gemstones in the world, because of all the known precious stones only an opal can show the complete range of spectral hues in glorious balance. The fascinating subject of Australia’s premier gem is opened up to the reader in this practical and authoritative field guide. Written especially for the opal collector and gemmology student, as well as for the opal miner or visitor to the opal fields, this book names every recorded opal deposit in Australia and pinpoints every location on concise geological maps.

The text clarifies in understandable terms the many mineralogical, gemological, and commercial complexities of the opal gems-tone and explains the scientific factors involved in opal formation.

The author traces the history of the Australian opal industry and shows that, although it has an annual turnover of tens of millions of dollars, it is a remarkably casual, disorganised, and unoriented business operation.

He shows the reader how to assess the value of opals and gives a comprehensive description, with full-colour photographs, of all the main opal patterns.”