12.10 Ct. Bi Color Ametrine from Ceylon (Sri Lanka)

One beautiful transparent 12.10 carat oval shape bi color ametrine is presented with dimensions of 17.05 by 13.16 by 9.31 millimeters, faceted to exacting standards to preserve weight while optimizing optical performance, and cut in a Portuguese cut known for its high facet density and dramatic scintillation, which transforms a single rough crystal into a gem with layered brilliance and a lively pattern of light return. The piece displays a balanced oval outline with proportional length to width ratio, a well centered table and crown, and a pavilion depth that supports both strong internal reflection and lively dispersion, resulting in an engaging face up presentation. Transparency is high throughout the stone, classified as transparent, allowing the full depth of the bicolor zoning to be appreciated from multiple viewing angles. The finish is described as an excellent polish, reflecting the final stages of lapidary craftsmanship where facet junctions are clean and meet with precise symmetry, and where surface luster approaches the theoretical limit for natural quartz varieties.

The Portuguese cut selected for this ametrine emphasizes a sophisticated faceting scheme that increases the apparent fire and scintillation compared to more conventional oval faceting styles, through a higher count of crown and pavilion facets and carefully calculated facet angles, which together produce a tessellated light return that accentuates the bi color nature of the material. In skilled hands the Portuguese cut requires meticulous planning during preforming to align the color zones with the facet layout, and to position the pavilion angles to avoid windowing or excessive extinction, while maintaining weight retention. The cutter achieved exceptional symmetry and facet alignment, visible in the crispness of facet junctions and the consistency of light patterns during rotation. The polish quality is excellent, indicating that the final stages of lap grinding and polishing were executed with fine abrasives and controlled pressure, preserving facet flatness and minimizing micro abrasion, which in turn maximizes brilliance and reduces the appearance of any minor surface features.

Color presentation for this Ceylon origin ametrine is medium in intensity, with a natural bicolor distribution that transitions from amethyst purple to citrine golden within the single crystal, providing a pleasing contrast that is neither washed out nor overly saturated, supporting good face up balance in most lighting conditions. The bicolor zoning appears as a gradation across the table and crown, and the Portuguese cut enhances the color separation by scattering light through multiple small facets, producing localized flashes of purple and golden tones rather than a harsh boundary line, which is frequently desirable in collectors pieces. Clarity is graded as very very slightly included when evaluated at eye level, indicating the presence of minute internal features that are not obtrusive under normal inspection and do not significantly interrupt the path of light, thus preserving strong brilliance and contrast. There are no enhancements reported for this gem, which means its coloration and clarity are natural, making this specimen particularly valuable to connoisseurs who prefer untreated material, and the provenance of Ceylon adds an additional element of interest for collectors familiar with regional crystallization habits and geological context.

On the Mohs scale of mineral hardness this specimen, being quartz family material, rates at seven, which places it well above many common gem materials and ensures a useful balance between wear resistance and workability, and it remains substantially harder than materials such as fluorite and calcite while being softer than topaz, corundum and diamond, with these reference points being diamond at ten, corundum at nine, and topaz at eight. A hardness of seven means the gemstone resists everyday abrasion and will retain polish and facet integrity under normal wear, however proper setting design is recommended for high wear items such as rings, employing protective bezels or low exposed girdle positions to mitigate risk from sharp impacts or prolonged edge contact, while pendants and earrings will exhibit excellent longevity with standard jewelry handling. Cleaning and care are straightforward for natural, untreated quartz, with warm soapy water and a soft brush suitable for routine maintenance, and professional cleaning methods including controlled ultrasonic treatments are typically compatible, although care should be taken with any mechanical impacts and sudden thermal shocks. This piece is offered by The Natural Gemstone Company, and it combines technical precision in cutting, a natural and attractive bicolor phenomenon, and practical durability, making it an attractive option for knowledgeable buyers seeking a technically interesting, collectible, and wearable ametrine specimen.