1.90 Ct. Grey Star Sapphire from Ceylon (Sri Lanka)

This specimen is a translucent 1.90 carat oval shape grey star sapphire from Ceylon, presented in a classical cabochon cut with dimensions of 8.21 by 6.62 by 3.33 millimeters, supplied by The Natural Sapphire Company. The weight to dimension ratio indicates a well proportioned gem for an oval cabochon, with a dome height that supports a strong asterism while retaining comfortable thickness for setting. Color is graded as very light intensity grey, a subtle tonal field that allows the star to contrast without overwhelming saturation, and the clarity is evaluated as eye clean at normal viewing distances, which means that any silk inclusions responsible for the star are finely oriented and not obtrusive to the unaided eye. There is no enhancement, the gem is unheated and otherwise untreated, and the polish quality is excellent, producing a smooth, mirror like surface across the dome that assists in star visibility and overall luster. The combination of origin, clarity, and absence of enhancement gives this stone provenance and marketability, while its modest size and weight make it versatile for both collectors and high quality bespoke jewellery.

Optical and structural characteristics are central to the performance of this star sapphire, and this cabochon exhibits asterism generated by aligned rutile silk inclusions intersecting the basal and prism directions of corundum, producing a six rayed star when illuminated with a single point light source. The very light body color increases translucency, allowing light to penetrate and interact with the internal silk, which in turn sharpens the star line definition against the pale grey background. The dome curvature is sufficient to focus the star toward the crown, while the cabochon symmetry ensures that the star is centered with predictable movement under changing light angles. Corundum refractive index in the range of approximately 1.762 to 1.770 and specific gravity near 4.00 inform the cutter on material behavior during shaping and polishing, and the gem hardness of 9 on the Mohs scale guarantees excellent wear resistance for everyday jewellery when properly set. Pleochroism in grey sapphires is minimal, which aids in maintaining uniform appearance across different orientations, and the eye clean clarity grade confirms that inclusions are principally fine silk rather than disruptive crystals or cavities.

Craftsmanship is apparent in the cabochon profile and polish technique, where the decision to preserve thickness at the girdle and maintain a consistently convex dome reflects an intent to maximize asterism while minimizing risk during cutting. The excellent polish is achieved through progressive abrasives and final rouge work, yielding low surface scattering and high specular reflection, both of which enhance star contrast and the perceived depth of the gem. For setting, designers should orient the stone so that the star aligns with the intended visual axis of the piece, and protective bezel or partial bezel settings are recommended to shield the high dome from knocks while still allowing the star to read clearly. Cleaning is straightforward, using warm soapy water and a soft brush, ultrasonic cleaners are generally acceptable for untreated corundum but caution is advised with stones showing dense silk zones, and exposure to harsh acids or prolonged high heat should be avoided to preserve the natural appearance. As an unenhanced Ceylon star sapphire with documented dimensions, weight, and eye clean clarity, this gem represents a technically interesting and collector worthy example of asteriated corundum, and it is offered with full disclosure and support from The Natural Sapphire Company.