6.15 Ct. Blue Sapphire from Ceylon (Sri Lanka)

This GGTL certified blue sapphire offered by The Natural Sapphire Company is a 6.15 carat cushion shaped gem, with precise dimensions of 10.99 by 9.11 by 6.28 millimeters. The gem has been fashioned with a mixed brilliant cut, combining brilliant style facets on the crown with controlled step or modified facets on the pavilion to balance color and light performance. The stone originates from Ceylon Sri Lanka, and exhibits vivid color intensity with heat treatment enhancement, and an excellent polish. Measured against its outline and depth, the pavilion depth relative to average girdle diameter is approximately sixty two and a half percent, a proportion that supports strong light return while preserving the saturated blue that defines fine Ceylon material.

The mixed brilliant faceting approach on this cushion profile is engineered to accentuate both color saturation and scintillation. The crown presents a network of kite and triangular facets that break incident light into numerous small flashes, while the pavilion facets are organized to reflect that light back through the crown in a concentrated manner, preserving hue intensity rather than dispersing it. Facet junctions are sharply cut and well aligned, and the excellent polish ensures minimal surface diffusion, so specular highlights appear crisp. The cushion outline with gently rounded corners enhances the visual spread, producing the perception of a larger face up area while maintaining the deep color in the pavilion, a desirable attribute for gems where color is the primary value component.

Clarity is graded as very very slightly included, evaluated at eye level, which for this stone denotes that the inclusions are minor and do not detract from the gem when viewed without magnification. The inclusions are small, well distributed, and serve minimally to interrupt light pathways, which allows the mixed brilliant architecture to produce steady scintillation and even color distribution. The vivid color intensity paired with eye level clarity yields an appearance that reads as both richly saturated and transparent, rather than dark or cloudy. Heat treatment in this case is a standard and stable enhancement applied to improve color uniformity and remove certain diffusion features, and it preserves the gemological integrity and durability of the sapphire.

When compared to more common blue gemstones the optical behavior of this sapphire stands out. Relative to blue topaz, which has a lower refractive index from around 1.61 and typically lighter saturation, this sapphire returns more light per facet and maintains deeper chroma, so it appears more luminous and alive in mixed lighting. Compared to aquamarine, which tends to be paler and has a lower refractive index, the sapphire shows superior color contrast and stronger scintillation. Against tanzanite, which can display strong pleochroism and a refractive index near 1.70, the Ceylon sapphire's color stability and higher refractive index from about 1.76 to 1.77 yield more consistent face up brightness and a different kind of brilliance that favors white light return and intense blue saturation. Compared to diamond, sapphires have lower dispersion and therefore less fire, but sapphires benefit from higher chroma and greater color depth, which translates into a type of brilliance that is more about vivid color play and lively flashes than the spectral fire that diamonds display.

Beyond optical performance, this sapphire offers superior wearability and practical advantages for those who value durability and everyday wear. Sapphire rates nine on the Mohs scale, making it significantly more resistant to abrasion than blue topaz and aquamarine, and better suited to secure bezel or prong settings that expose more of the crown for maximum light interaction. For design integration, a four prong or well proportioned bezel setting will preserve the cushion silhouette while allowing the mixed brilliant facet strategy to operate effectively under typical wear conditions. As a Ceylon specimen with GGTL certification and documented heat treatment only, this sapphire represents a blend of provenance, craftsmanship, and technical merit, and invites settings that emphasize its color and scintillation. For precise evaluation and bespoke mounting options please contact The Natural Sapphire Company, we can provide the GGTL report, additional lighting images, and custom design guidance to optimize the gem for your intended use.