The star imprisoned in the heart of this asterated ruby from Sri Lanka is due to tiny crystals of rutile formed through a process of exsolution, where excess titanium was squeezed out of solution. Unable to grow freely, it was constrained by the host corundum structure, forced to crystallize in three directions in the host’s basal plane. The result is simple magic—a magnificent star—yet another wonder that is the microworld of gemstones.
Natural Star Ruby • Sri Lanka (Ceylon) • Enhancements: None Detected (None) • Lighting Conditions: Fiber Optic: Overhead
Photographer: Richard W. Hughes •
Image Number: A-001-4422-1 • Field of View = 5 mm • Date Posted: 26 January 2016
Koivula, J.I. and Hughes, R.W. (2005) Following the Silk Road: Rutile in corundum. Bangkok, Lotusgemology.com, RWHL*.
Tschermak, G. (1878) Optisches Verhalten von Korund-Krystallen [Optical behavior of corundum crystals]. Mineralogische und Petrographische Mittheilungen, Vol. 1, No. 4, pp. 362–364; RWHL*.