0.66 Ct. Yellowish Green Sapphire from Ceylon (Sri Lanka)

This 0.66 carat princess shape yellowish green sapphire measures 4.65 x 4.57 x 3.27 millimeters, a compact square with a pavilion depth that yields an overall depth of approximately 71 percent, and it presents as a transparent, faceted gem with an excellent polish. The cutting style follows a modern princess configuration, where crisply defined square pavilion facets meet in a central culet area to produce a highly directional light return. The crown is faceted to optimize table brilliance while preserving face up color, and the precise facet junctions and proportions produce strong specular highlights across each bezel and pavilion facet. With the very slightly included clarity grade evaluated at eye level, inclusions are minimal and localized, permitting clean light transmission and crisp facet reflections without significant scattering. The exceptional polish ensures that the surface reflectance approaches the theoretical limit for corundum, delivering sharp, well defined facets that contribute to pronounced contrast and scintillation, qualities that are especially important in a square brilliant silhouette.

Color and material characteristics are integral to the performance of this sapphire, and the stone exhibits a light color intensity in a yellowish green hue that originates from its Ceylon provenance. Sri Lankan corundum is well known for producing lively pastel tones and subtle modifiers in the yellow to green range, and this specimen demonstrates that pedigree with a delicate balance between yellow warmth and a green coolness depending on viewing angle and illumination. Corundum can exhibit pleochroism, and this sapphire shows a modest shift between greener and slightly yellower facets as the stone is rotated, a behavior that interacts with the princess faceting to create changing internal reflections. The gem has been heat treated, a standard and stable enhancement for Ceylon sapphires, which in this instance has reduced rutile inclusions and refined the crystal lattice to enhance transparency and color uniformity, while leaving natural zoning and crystal character intact. The very slightly included clarity at eye level indicates that the heat treatment has been effective in improving overall appearance without masking the stone s natural identity, and the combination of light intensity, polish, and minimal inclusions delivers a lively, airy presence when mounted.

When comparing reflective qualities to other gemstones in its category, several optical parameters clarify why this yellowish green sapphire performs as it does. Corundum has a refractive index in the range that produces a strong vitreous to subadamantine luster, which is higher than that of common silicates such as quartz or diopside, and slightly higher than many spinels and tourmalines, resulting in crisper facet reflections and tighter scintillation. The dispersion of corundum is relatively low compared with diamond, so fire or spectral color separation is modest, yet the high refractive index ensures efficient light return and pronounced contrast between light and dark facet areas. In direct comparison to blue sapphires of similar cut and weight, the reflective behavior is governed primarily by hue and tone rather than by refractive index, so a yellowish green sapphire will typically present broader, warmer flashes with a tendency toward bright specular highlights on the crown facets, whereas a saturated blue sapphire of equivalent cut may emphasize deeper, more concentrated flashes with greater apparent depth. Against gemstones such as peridot or green tourmaline, which have lower refractive indices and different dispersion profiles, this sapphire will appear to have a firmer, more adamantine surface luster and crisper facet boundaries, producing the perception of higher polish and greater structural integrity in the reflections.

For buyers focused on exacting optical performance, this Ceylon princess cut sapphire from The Natural Sapphire Company offers a technical balance of proportion, finish, and material quality. The square brilliant geometry capitalizes on corundum s optical constants to deliver directional brilliance and lively scintillation, while the light yellowish green color and very slightly included clarity present a gem with transparent body color and minimal internal disruption. Heat treatment has been applied in a controlled manner to enhance color and clarity without compromising stability, and the excellent polish and close symmetry maximize the stone s effective refractive behavior. When set in jewelry that emphasizes facet orientation and light access, this sapphire will return light with a distinct, sharp luster that stands apart from lower index green gemstones, and it will offer a nuanced, changing palette of yellow and green flashes that will appeal to collectors and connoisseurs who value technical craftsmanship and optical precision.