Rare Large Polished Light Opal Specimen. Lambina Cattle Station, South Australia

Weighing approximately 1398.5 carats and measuring 4 x 3 x 1 in (105mm X 70mm X 35mm) - Sold for $19,200

In a remote region of South Australia, opal was first discovered at Lambina during the depression years of the early 1930s. A minor rush occurred in the 1980s following discoveries by some miners at Seven Waterholes diggings. A discovery of high quality stones in 1996 led to a renewed rush of claims being made, however, before many of these claimed could be processed, the Wik native title decision halted any new mining. In December 1997, miners were informed that a native title claim would be lodged over the entire Mintabie area. Negotiations between miners and native title holders since then have allowed mining to continue. Lambina now supports a population of around 300 and produces a major portion of South Australia's opal—specimens retrieved from this locality are known as “Lambina Opal”.

The present opal, found in 2001, was left dry for six years before polishing to ensure its stability. Technically speaking, it is classed as “light opal”, (a designation which is a better quality than “white” opal)—which is a category between “white” and “crystal” opal in value. It has been polished on both sides, as a free form large piece. It is remarkable for its pinpoint play-of-color in hues of electric blue, vivid lime green, orange and yellow and flashes of purple at the sides. Stones of this size, with color on both sides and without fractures, are very rare. (Copyright © 2002-2008 Bonhams 1793 Ltd., Images and Text All Rights Reserved)

Bonhams. Natural History, 22 Jun 2008. 220 San Bruno Street, San Francisco // 7601 Sunset Blvd., Los Angeles. www.bonhams.com