3.19 Ct. Blue Cabochon Sapphire from Ceylon (Sri Lanka)

This gem is a translucent, oval shape blue sapphire weighing 3.19 carat, with finished dimensions of 9.15 x 7.19 x 4.79 mm. The cutting style is cabochon, exhibiting a smooth domed crown and a flattened pavilion that emphasize body color rather than faceted brilliance. The stone displays intense color intensity, with the visual impression of deep blue saturation across the major viewing angles. Clarity is graded as included, evaluated at eye level, which indicates the presence of internal features visible without magnification, yet not affecting the overall uniformity of color when set. Surface polish is graded excellent, producing crisp specular highlights on the dome and a high gloss finish that contributes to surface luster. Enhancement is heat treated, consistent with common lapidary practice to stabilize and intensify blue tone in sapphires. Origin is Ceylon, Sri Lanka, a provenance known for producing sapphires with a characteristic velvety to lively blue, and this specimen reflects that regional character in its color and translucency. The Natural Sapphire Company presents this gem with full disclosure of its gemological parameters to facilitate informed assessment by connoisseurs and designers.

From a lapidary perspective, the cabochon execution on this oval sapphire demonstrates disciplined control of dome height and symmetry to manage light transmission and color saturation. The dome rise relative to the 4.79 mm total depth has been optimized to avoid windowing, a phenomenon where a shallow pavilion allows light to pass through and reduce perceived color depth. The oval outline dimensions yield a length to width ratio that is visually balanced, promoting even color distribution across the table area. Polishing technique is evident in the uniformity of specular reflections with minimal orange peel or facet pinpointing, indicating consistent abrasive progression through fine grits to final compounds. Internal inclusions in included grade material are likely to consist of silk like rutile needles and possible crystal or fingerprint features, which in cabochons often scatter light to produce a softening of highlights and contribute to the translucent, velvety appearance. When setting a cabochon, orientation of the material relative to the crystallographic axes can be chosen to optimize pleochroic color display, where present, and practical mounting must account for the cabochon dome to avoid edge chipping during bezel seating.

Material properties of corundum are relevant for both handling and valuation, and this sapphire adheres to expected physical parameters for natural sapphire. Refractive index for corundum lies approximately between 1.762 and 1.770, resulting in moderate brilliance in faceted stones but in cabochons contributing to internal light diffusion and depth. Specific gravity is near 4.00, which correlates with the substantial apparent heft of a 3.19 carat cabochon of these dimensions. Hardness on the Mohs scale is 9, making the stone well suited for daily wear, though the domed profile should be protected from sharp impacts to prevent chipping at the girdle. Spectral analysis of natural blue corundum typically shows iron related absorption features and a residual chromium component in some colors, and heat treatment commonly reduces silk and refines color by altering trace element distribution or dissolving rutile, without introducing foreign filling materials. The present stone is heat treated only, and its polish quality and surface integrity indicate the absence of surface reaching fractures or glass filling. For the gemological buyer, these properties inform both setting strategy and long term care.

Design and setting recommendations emphasize the cabochon form factor and the specific dimensions of 9.15 x 7.19 x 4.79 mm. Bezel mounting is the preferred approach for cabochons to protect the dome and secure the stone with minimal risk of side impact, and a low profile bezel that follows the oval perimeter will present the gem flush to the mounting plane while allowing the dome to read its full color saturation. Alternately, a partial bezel or prong cup with a secure lip can be employed in custom settings where greater metal visibility is desired, though additional attention to seat depth and pressure distribution is required to avoid stress concentrations at the girdle. Metal choice influences perceived color, with warm alloys such as yellow gold providing contrast that can warm the stone visually, while white metals such as platinum or white gold emphasize cool blue tonality and the silvery highlights on the dome. Given the included clarity grade, lighting and background will affect apparent uniformity, therefore appraisal should consider specimen photography under standardized daylight equivalent illumination for accurate color matching with other gemstones or center stones in paired designs. The Natural Sapphire Company offers this Ceylon origin, heat treated cabochon with documentation of weight, dimensions, cut style, clarity grade, polish and enhancement type, providing the technical transparency expected by discerning collectors and jewelry designers, and guidance on mounting, handling and care is available on request.