1.18 Ct. Moonstone from Ceylon (Sri Lanka)

This specimen from The Natural Gemstone Company is a transparent rainbow moonstone weighing 1.18 carat, presented in a refined cushion outline with dimensions of 7.09 x 6.54 x 4.34 mm. The gem is fashioned in a mixed brilliant cut that marries brilliant crown facet geometry with a modified pavilion, engineered to balance scintillation and the internal adularescent effect that defines premium moonstone. Color intensity is described as faint, a neutral field that permits the spectral flashes to read cleanly without the masking effect of body color. Clarity is graded very slightly included at eye level, a practical grade for moonstone that signals high transparency with minute natural features that will not detract from typical wear or mounted presentation. Polish is excellent, indicating precise facet junctions and a smooth table surface, and there has been no enhancement to alter the material, preserving the stone in its natural state. Provenance is Ceylon Sri Lanka, a region known for producing moonstones with layered feldspar structures that promote vivid adularescence and subtle rainbow sheens.

The mixed brilliant cut on this cushion silhouette is executed to emphasize both light return and the characteristic adularescence that informs the rainbow nomenclature. On the crown, a modified brilliant arrangement of star, bezel, and upper girdle facets disperses incoming light across the table and crown angles, creating scintillation while also channeling light into the internal lamellar layers. The pavilion utilizes a combination of elongated facets and modified steps to manage optical path length and internal reflection, so that the adularescent plane is intersected in multiple orientations as the gem is tilted. This approach avoids a single fixed flash, producing intermittent spectral banding as the viewing angle changes. Facet proportions are tuned to the 4.34 mm depth to avoid light leakage while retaining a comfortable crown height that accentuates the soft rounded corners of the cushion shape. The result is a lively, multidirectional display, where the faint body color serves as an unobtrusive backdrop that allows blue and rainbow flashes to manifest with clarity. The excellent polish enhances this behavior by minimizing microfacet diffusion, preserving crisp facet edges that read well under magnification and to the unaided eye.

Inclusions are described not as flaws but as intrinsic identifiers and character marks that testify to the gemological history of this moonstone. The material displays fine lamellar twinning and microscopic platelets arranged on subparallel planes, together with occasional fine needle like inclusions and fluid related growth features. These internal structures are common in feldspar family minerals and are the very interfaces that scatter light to produce the adularescent effect. At eye level the inclusions are very slight, usually seen only as delicate wisps or faint linear features when viewed closely, and they serve as a unique internal fingerprint that differentiates this specimen from cut rivals. Under loupe or microscope, the arrangement of platelets and twinning presents a diagnostic pattern, useful for identification and for confirming the untreated nature of the stone. For settings and care, the natural stability of moonstone favors secure mounting with a protective bezel or partial bezel to minimize edge chips, while a slightly open gallery is recommended to allow light to enter the pavilion and invigorate the adularescent play. Avoid thermal shock and harsh ultrasonic cleaning, and opt instead for gentle soap and warm water with a soft brush to preserve the excellent polish and the subtle internal architecture. This Ceylon rainbow moonstone, with its measured proportions, considered faceting, and authentic inclusions, offers a connoisseur quality specimen that combines technical refinement with the singular character only natural internal features can provide.