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

One transparent 0.90 carat oval shape yellowish green sapphire, dimensions 7.03 by 5.00 by 2.72 mm, presents a balanced combination of color, clarity, and cut. The gem is fashioned in a mixed brilliant cut and carries a clarity grade of very very slightly included, evaluated at eye level. Its color intensity is classified as intense, and the surface finish is described as excellent polish. No enhancement has been applied to this stone, and its reported origin is Ceylon, Sri Lanka. The Natural Sapphire Company provides this detail set to document the material attributes that underlie the stone performance in light, and to ensure a clear understanding of its natural, unmodified optical qualities.

The inherent sparkle of this sapphire is rooted in its material structure as corundum and in the way the cutter has translated that structure into a faceted geometry. Corundum crystallizes in a trigonal lattice which yields a relatively high refractive index. A higher refractive index increases the degree to which light is slowed and bent upon entering the stone, promoting internal reflection and light return to the viewer. The modest birefringence and the potential for pleochroism in sapphire mean that slight directional differences in light transmission can accentuate shifts in tone, especially in a yellowish green hue. When combined with a precise mixed brilliant cut, these optical characteristics deliver a complexity of flashes and color variation that single facet arrangements cannot match. The cutter exploited the material constants by arranging brilliant style facets on the crown to maximize scintillation, while employing a pavilion scheme that controls the angles of internal reflection, thereby maintaining a consistent light pathway back through the table.

Beyond the intrinsic optical constants, the gem shows structural and cutting details that are specifically responsible for its refined sparkle. The oval outline elongates the light path through the stone, allowing rays to traverse a greater portion of the material before exiting, and this increases the opportunities for internal refraction and dispersion. The mixed brilliant cut uses smaller, well proportioned crown facets that generate frequent, high contrast flashes, and a pavilion geometry tuned to the dimensions of the 7.03 by 5.00 by 2.72 mm body that encourages efficient light return rather than leakage. The excellent polish reduces microscopic surface scatter, preserving specular reflection from each facet and enabling crisp, mirror like highlights. The intense color and high transparency mean that light penetrates without undue absorption, so the balance between color saturation and light return produces lively, concentrated flashes rather than muted glow. The very very slightly included clarity grade, determined at eye level, indicates that inclusions are minor and do not interrupt the principal light paths, so the visual field remains open and active. In practical terms, the result is a dynamic interplay of bright and dark facet contrasts, rapid scintillation on movement, and a cohesive body color that refracts and reflects light with clarity and depth.

From a practical and design perspective, this sapphire combines optical performance with durability and provenance. As a natural Ceylon material with no enhancement, the stone retains its original zoning and internal structure, characteristics that connoisseurs and gem professionals value for their contribution to natural light behavior. The 0.90 carat weight and modest dimensions render the gem suitable for center settings that allow light access from multiple angles, such as bezel open gallery designs, four prong or six prong mounts, and halo contexts where surrounding stones can complement the sapphire glare. The hardness and toughness typical of corundum confer resilience appropriate for daily wear, while the excellent polish and calibrated facet work mean the stone will maintain its optical performance over time when set with proper protection. The Natural Sapphire Company documents origin, cut, and enhancement status as part of our standard information set, to assist in matching the gem to both design specifications and performance expectations. For those assessing gemstones on the basis of how structure produces sparkle, this sapphire offers a demonstrable example of how material physics and considered cutting practice converge to create a gem with measured brilliance, scintillation, and color saturation.