11 Dec 2012
13:00 PST
Los Angeles
The World of Opals, The Splendor of Gold including the Margie and Robert E. Petersen Collection of Gold Nuggets
Back to auction 21137
The World of Opals, The Splendor of Gold including the Margie and Robert E. Petersen Collection of Gold Nuggets
Back to auction 21137
Very Fine Black Matrix Opal Specimen
Andamooka, South Australia, Australia
Like all matrix opal material from this region this specimen was sugar treated by the miners before being honed to a superb level of polish. The process—a classic and long-standing tradition—involves soaking the original rough specimen in a sugar solution and then boiling it in acid to deposit carbon in the available pore spaces, resulting in a dark background. The procedure is performed to reveal the excellent pinpoint fire and play-of-color of the mineral within the matrix. The present cabinet-sized specimen, has been contour polished on all surfaces to reveal its pinpoint play-of-color on one side and large patches of color on the reverse.
Weighing approximatly 443.5 carats and measuring 6.0 x 4.5 x 4.0cm
Like all matrix opal material from this region this specimen was sugar treated by the miners before being honed to a superb level of polish. The process—a classic and long-standing tradition—involves soaking the original rough specimen in a sugar solution and then boiling it in acid to deposit carbon in the available pore spaces, resulting in a dark background. The procedure is performed to reveal the excellent pinpoint fire and play-of-color of the mineral within the matrix. The present cabinet-sized specimen, has been contour polished on all surfaces to reveal its pinpoint play-of-color on one side and large patches of color on the reverse.
Weighing approximatly 443.5 carats and measuring 6.0 x 4.5 x 4.0cm
Estimate:
US$ 7,000 - 9,000
£4,500 - 5,700
€5,200 - 6,700
£4,500 - 5,700
€5,200 - 6,700
Category: Natural History
Auction terms and conditions
Contacts
Claudia Florian
Bonhams
Work
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Los Angeles,
90046
United States
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Specialist
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Natural History
