Publications

MOON, AR & PHILLIPS, MR 1984, 'AN ELECTRON-MICROSCOPY STUDY OF EXSOLVED PHASES IN NATURAL BLACK AUSTRALIAN SAPPHIRE', MICRON AND MICROSCOPICA ACTA, vol. 15, no. 3, pp. 143-146.
View/Download from: Publisher's site
View description>>

NA

Moon, AR & Phillips, MR 1984, 'The physics of asterism in sapphire.', Schweizerische Mineralogische und Petrographische Mitteilungen, vol. 64, no. 3, pp. 329-334.
View description>>

The star image in silky sapphire (asterism) is shown to result from the incoherent superposition of reflected Fraunhofer diffraction patterns. These arise when light is scattered from precipitates strictly oriented within the sapphire host. The theory explains why long, thin precipitates produce sharper stars than their shorter and wider counterparts and why a cabochon is normally required to observe the star image. -W.S.