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 processa classic and long-standing traditioninvolves 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