1.50 Ct. Blue Sapphire from Ceylon (Sri Lanka)

This transparent 1.50 carat radiant shape blue sapphire measures 7.88 x 4.71 x 4.09 millimeters, with a length to width ratio of approximately 1.67, and a depth of about 65 percent of the average of the length and width. The stone is fashioned in a radiant cut, a hybrid faceting scheme that combines step facets on the crown with brilliant facets on the pavilion, creating a controlled balance between broad flash and compact scintillation, the overall facet count approximating seventy facets. Clarity is graded as very very slightly included at eye level, the inclusions minimal and localized, and they do not compromise transparency or light return. Color intensity is described as intense blue, the saturation strong and even across the table, and the surface finish is an excellent polish, yielding crisp facet junctions and minimal surface diffusion. Enhancement status is no enhancement, and provenance is Ceylon Sri Lanka, attributes that are important to connoisseurs, and that are documented and verifiable by The Natural Sapphire Company.

From a chromatic and optical engineering perspective this Ceylon sapphire exhibits the classic Sri Lankan tendency toward bright, lively blue with a medium to favorable tone that allows internal reflections to read as a vivid blue under mixed lighting. Intensity here refers to saturation rather than darkness, and the radiant cut has been proportioned to favor color dispersion and uniformity across the table while maintaining strong return of light through the pavilion. The stone shows pleochroic behavior consistent with corundum, with a primary face up blue hue and subtle shifts toward a cooler blue green when viewed off axis, a characteristic that the cutter accounted for by orienting the pavilion and crown facets so that the predominant face up color is the most saturated and appealing. Because there is no heat or other enhancement, the intense hue is wholly natural, and the combination of color and clarity produces excellent apparent transparency, allowing the stone to read lively even under less than ideal illumination.

Optically this sapphire performs in a way that is predictable for corundum, and understanding the material constants helps to place its reflective qualities in context. Corundum has a refractive index of approximately 1.762 to 1.770, and a dispersion of about 0.018, values that explain why sapphires display good brilliance and flash but show less spectral fire than gemstones with higher dispersion values. For comparison the refractive index of diamond is about 2.417 with dispersion near 0.044, which accounts for diamond fire that corundum cannot match. Within the colored stone category a spinel typically has a slightly lower refractive index around 1.712 to 1.736, so a well cut sapphire will generally return light with a slightly stronger presence and a crisper contrast pattern than a comparable spinel, and the sapphire will present a slightly higher luster. Tanzanite, with a refractive index in the lower range around 1.687 to 1.707 and pronounced pleochroism, will show more color shifting and less sustained brilliance than corundum, particularly in higher brightness environments. Ruby, being the same species as sapphire, has essentially identical optical constants, so reflective behavior is comparable, and differences between a blue sapphire and a ruby are driven largely by hue and saturation rather than intrinsic reflectivity.

From a craftsmanship and practical design standpoint the attributes of this 1.50 carat radiant sapphire make it highly versatile, and the combination of a precise radiant faceting plan, excellent polish, and very very slightly included clarity allows gem setters to exploit both brilliance and color. The crisp facet junctions and even pavilion depth support lively scintillation when set in open settings that permit light to enter through the girdle and table, prong settings being particularly effective at maximizing return, while halo settings can enhance perceived size and emphasize the stone color by contrast. The excellent polish reduces surface scattering, which improves contrast and the apparent saturation of the blue, and the lack of enhancement preserves natural body color for collectors who prioritize provenance and origin, attributes The Natural Sapphire Company documents and supports. Additionally corundum has a hardness of nine on the Mohs scale, which provides durable wearability for daily settings while still responding well to precision repolishing or recutting if future preferences change. For buyers who evaluate gemstones on technical merit, this Sri Lankan radiant sapphire combines an optimal length to width ratio, a facet architecture tuned to corundum optical constants, strong natural color, and eye level clarity, making it an exemplary choice for collectors and design driven commissions alike, available through The Natural Sapphire Company.