0.80 Ct. Bi Color / Parti Sapphire from Ceylon (Sri Lanka)

This bi color parti sapphire begins its story deep within the alluvial and primary deposits of Ceylon Sri Lanka, where complex geological processes produced a corundum crystal with clear zoning of chromophores. In the field the rough exhibited distinct areas of blue and yellow green saturation, a characteristic which immediately informs the cutting plan, and the decision to preserve both hues rather than attempt to homogenize color through excessive material removal. From the moment the rough is extracted, the journey is governed by technical choices, starting with orientation. Orientation is determined using polariscopic and chelsea stone assessment to map pleochroic axes and locate internal features, and the cutter uses a combination of transmitted light and immersion techniques to reveal twinning planes and pinpoint inclusions. The rough for this piece was selected for its transparency and favorable crystal habit, enabling a round outline while preserving as much weight as possible to reach the finished 0.80 carat target, and the rough to finished planning phase included estimating yield, defining the ideal diameter to depth ratio, and calculating facet angles to balance color dispersion and light return.

The cutting style applied to this gemstone is faceted with a mixed brilliant scheme, executed to reconcile the parti color distribution with optical performance. The finished dimensions are 5.87 by 5.84 by 3.08 millimeters, producing a depth ratio of approximately 52.6 percent, a proportion that favors strong face up color while maintaining efficient pavilion geometry for return of light. The mixed brilliant approach combines a brilliant cut crown with a stepped or modified pavilion, a solution chosen to control windowing through the yellow green zone while optimizing scintillation from the blue zone. During bruting and preforming the cutter established a precise girdle profile to maintain round symmetry within a tolerance measured in hundredths of a millimeter, and faceting proceeded with calibrated index gear settings to define crown angles and pavilion angles to within a tenth of a degree. The crown facets were polished to encourage dispersion without sacrificing color saturation, while the pavilion facets were optimized for total internal reflection across the stone’s pleochroic axes, achieving a balance between fire and broad flash suited to the sapphire’s vivid intensity.

Clarity and treatment history are paramount for connoisseurs, and this sapphire carries a clarity grade of very slightly included, evaluated at eye level, with inclusions that are typical of natural corundum, including fine crystal fingerprints and minute healed fractures. These internal features were assessed during the planning stage, and facet placement was used strategically to minimize their visibility in face up viewing, placing pavilion facets and culet positioning to obscure inclusions that would otherwise impact apparent clarity. The polish is excellent, achieved through progressive laps and diamond abrasives with controlled lubrication and polishing times to remove submicroscopic surface damage while preserving facet crispness. Importantly this gem has no enhancement, it has not been subjected to heat treatment, diffusion, or fracture filling, and its vivid color intensity reflects its natural chromium and iron titanium zoning. The origin Ceylon Sri Lanka contributes to the stone’s character, Ceylon sapphires are known for a particular brightness and clarity of tone, and the parti nature here produces an appealing interplay between saturated blue and a lively yellow green, with pleochroic shifts that show different hues along orthogonal viewing angles, an effect that informed both facet count and facet placement during cutting.

From final polish the sapphire was submitted to rigorous grading and documentation, with measurements recorded precisely to the hundredth of a millimeter, weight confirmed to two decimal places in carats, and visual assessments performed under standard daylight equivalent illumination and a 10 times loupe for inclusion evaluation. The result is a transparent round shape sapphire, 0.80 carat, with mixed brilliant faceting, vivid color intensity, very slightly included clarity at eye level, excellent polish, and no enhancement, provenance recorded as Ceylon Sri Lanka. For setting recommendations the technical considerations include an open or semi open back mounting to allow light to enter the pavilion and animate the parti colors, and a custom bezel or prong design that secures the girdle at the engineered tolerance while exposing optimal crown area for viewing the color interplay. At The Natural Sapphire Company we present this stone with full technical documentation and high resolution imaging, and we advise mounting choices that respect the depth ratio and facet geometry to preserve optical performance. This sapphire is a study in deliberate decisions from mine to market, each stage executed with precision to preserve natural color zoning, clarity, and brilliance, making the finished gem a technically refined and rare example for collectors and connoisseurs who value provenance and uncompromised craftsmanship.