Metal Sulfide in Spinel
A strikingly textured crystal, likely a metal sulfide, is suspended within a pink spinel; viewed under darkfield and diffuse fiber-optic lighting. The step-cut facets on the stone’s pavilion provide a sense of depth to the image. Photomicrograph by E. Billie Hughes; field of view 3.4 mm.
Recently, a 3.14 ct pink spinel was submitted to the Lotus Gemology laboratory, with encouragement from the owner to examine its inclusions. When viewed under the microscope, the spinel did not disappoint. Suspended within was a richly textured, opaque metallic crystal (see above). Although attempts were made to identify the inclusion using micro-Raman spectroscopy, its identity remained inconclusive. However, based on the crystal’s appearance, it was likely a metal sulfide. Similar inclusions in spinel have been reported as pyrite (E.B. Hughes et al., “Spinel inclusions: An exercise in aesthetics,” InColor, No. 43, 2019, pp. 66–73; N. Renfro et al., “Micro-features of spinel,” Spring 2021 G&G, pp. 46–49).
.jpg "YMAL GIA Ed")
