Corundum var. Sapphire,
Mt Painter Region SA.
Corundum is natural aluminium oxide (Al2O3), the second hardest mineral after diamond. It is used as an abrasive in applications such as optical grinding. World production is small and declining due to competition from synthetics including fused alumina and silicon carbide. Gem varieties are ruby (red) and sapphire (blue). (Fig 1, corundum localities within South Australia).
In 1910, unsuccessful attempts were made to mine corundum from the Corundum Mine deposit 6 km west of Mount Painter. The corundum occurs as sporadic granular masses and zoned crystals in a corundum–phlogopite schist lens within metamorphosed Palaeoproterozoic quartzite in the Mount Painter Inlier. Occurrences have also been reported from near the Woman-in-White Mine and near Ameroo Hill in the Willyama Inliers (Olary Province). Massive blue-grey corundum has been recorded within ultrabasic bodies in two localities south of Moorilyanna Dam on Tarcoonyinna Creek in the Musgrave Block. Ruby and sapphire have been recorded in gold-bearing alluvium at Daws Diggings, 42 km southwest of Kingscote on Kangaroo Island.
1cm blue corundum in quartz-kyanite vein, Brown's Kyanite Deposit, Mingary. (photo courtesy of Clark, C. 2003).
Blissett, A.H., 1976. Corundum in South Australia. In: Knight, C.L. (Ed.), Economic geology of Australia and Papua New Guinea, 4, Industrial minerals and rocks. Australasian Institute of Mining and Metallurgy. Monograph Series, 8:101.
Crooks, A. F. and Abbot, P. J., 2003. Corundum in South Australia. South Australia. Department of Primary Industries and Resources Report Book 2003/03. (pdf ~ 1.44Mb).