4.18 Ct. Bi Color Sapphire from Ceylon (Sri Lanka)

This exceptional, transparent 4.18 carat cushion shape bi color sapphire measures 10.75 by 8.62 by 5.01 millimeters, and has been cut to a mixed brilliant pavilion to optimize both color presentation and scintillation. Sourced from Ceylon, Sri Lanka, and offered by The Natural Sapphire Company, this gem presents a vivid color intensity that shifts between rich cornflower to deep blue and sunny golden yellow depending on viewing angle and light direction. The mixed brilliant cut combines the depth and color saturation benefits of a faceted pavilion with the surface reflections of a brilliant style crown, creating lively return of light across the breadth of the table while allowing the bicolor zoning to show as controlled flashes. The gem has an excellent polish that enhances surface luster and a clarity grade of very slightly included when evaluated at eye level, meaning inclusions are minimal and do not materially interfere with the stone’s transparency or visual performance to the unaided eye. The sapphire has been heat treated, a stable and widely accepted enhancement in the trade that improves color saturation and clarity while leaving the structural integrity and long term stability of the corundum intact.

From a gemological perspective this sapphire exhibits properties that make it both visually striking and technically desirable to educated buyers. Corundum, the mineral family that includes sapphire, has a refractive index of approximately 1.762 to 1.770 and a modest dispersion, which together produce a strong, velvety brilliance and crisp, colorful flashes rather than the fire seen in higher dispersion gems. The bi color nature of this specimen introduces additional visual complexity, because sapphires are pleochroic, showing different hues along different crystallographic axes. In this stone pleochroism contributes to the perception of color change across the cushion, enhancing visual depth and giving rise to localized reflections that alternate between deep blue and warm yellow. The clarity grading of very slightly included indicates that minor internal characteristics exist, but they are small, well-dispersed, and typically only detectable under magnification or careful examination. In combination with the excellent polish and considered facet architecture, those small inclusions do not detract from the stone’s brilliance or wearable elegance, and in some cases they can serve as microscopic fingerprints confirming natural origin.

Comparing the reflective qualities of this Ceylon bi color sapphire to other gemstones in its category highlights several advantages. Versus single-color sapphires with similar cut and clarity, a well-executed bi color sapphire offers a greater degree of dynamic contrast because of its zonal hues, producing a lively pattern of color flashes that catch attention more readily than a monochrome stone. Relative to other corundum sources, Sri Lankan sapphires are often noted for their bright, lively tones and good transparency, and this stone exemplifies that character while offering the added rarity of distinct bi-color zoning. Compared to spinel, which has an attractive luster but generally lacks strong pleochroism, the sapphire delivers more pronounced directional color shifts and slightly higher refractive index, translating into a more scintillating face-up appearance. Against tanzanite, which can show dramatic trichroism and strong violet-blue hues, this sapphire’s advantage is in durability, hardness, and surface retention of polish, providing comparable directional color interest with greater everyday resilience. The result is a gem that balances sparkle, color play, and toughness more effectively than many alternatives for jewelry that will be worn frequently.

For the informed buyer considering value, this sapphire’s combination of characteristics is compelling. A 4.18 carat size in a well-proportioned cushion is significant, and when paired with vivid color intensity, mixed brilliant cutting, and eye-level very slightly included clarity, it becomes a stone that commands attention while still offering investment sensibility. The disclosed heat treatment is standard practice, widely accepted and stable, and the Ceylon origin adds provenance that many connoisseurs prize for its historical association with quality blue and parti-color sapphires. From a setting perspective the cushion outline and moderate depth allow craftsmen to showcase the bi-color zoning without compromising light performance, and the excellent polish ensures that the facet junctions will reflect cleanly over time. At The Natural Sapphire Company we emphasize transparent disclosure and gemological context, and this sapphire represents the type of balanced, high-appeal offering that knowledgeable buyers seek when they want a piece that is both visually dynamic and technically sound.