This spinel contained a number of octahedron-shaped crystals filled with a transparent doubly refractive material, as well as hexagonal black plates of what is probably graphite. The doubly refractive nature of the filling becomes clear when the gem is viewed between crossed polars, as the inclusion lights up with interference colors against a black background. The ability of spinel to force its morphology on guest minerals has been dubbed “philoxenism” by John Koivula.
Natural Spinel • Not Determinable • Enhancements: None Detected (None) • Lighting Conditions: Diffuse Light Field + Crossed Polars
Photographer: Richard W. Hughes •
Image Number: A-003-4131-2 • Date Posted: 22 July 2019
Hughes, E.B., Koivula, J.I., Manorotkul, W., Renfro, N. and Hughes, R.W. (2019) Spinel inclusions: An exercise in aesthetics. InColor, No. 43, pp. 48–55.
Gübelin, E.J. and Koivula, J.I. (2005) Photoatlas of Inclusions in Gemstones, Volume 2. Basel, Switzerland, Opinio Publishers, 830 pp.; RWHL*.