25.90 Ct. Purplish Blue Star Sapphire from Ceylon (Sri Lanka)

This gem is a translucent, oval cabochon star sapphire weighing 25.90 carats, with dimensions of 16.11 by 13.96 by 10.43 millimeters. The body color reads as a purplish blue of medium intensity, and the cutting style is a classic domed cabochon that produces a distinct six-rayed asterism under direct illumination. Clarity is graded as slightly included at eye level, a characteristic that in this stone contributes to the pronounced star rather than detracting from its appearance. The polish is excellent, yielding a clean, reflective surface across the dome, and there has been no enhancement or treatment applied. Origin is Ceylon, Sri Lanka, a source renowned for sapphires with robust asterism, and the combination of natural silk inclusions and skillful cabbing in this piece is typical of fine untreated star sapphires from that region. The Natural Sapphire Company presents this stone with full transparency on its gemological attributes and a clear record of its natural, untreated status.

The proportions and visual presence of this 25.90 carat oval make it particularly well suited to single-stone statement pieces where the asterism can be properly oriented and appreciated. For rings, a low-profile bezel or partial bezel setting will protect the high dome while allowing the star to read clearly when the hand is viewed face-on; a directional orientation with the star centered perpendicular to the finger yields the most striking visual effect. As a pendant, the stone can be mounted with an open or gallery-back design to increase light transmission and emphasize translucency, or with a darkened closed back to intensify contrast and sharpen the star, depending on the desired aesthetic. Other practical settings include an elegant solitary brooch or a gentleman’s signet where the oval form and size provide balanced coverage. For earrings or multi-stone compositions, the stone’s substantial weight and unique star effect make it better suited to a single focal piece rather than paired small mounts, unless a custom-matching partner stone is created to match both color and asterism.

Choice of metal and complementary gems will influence how the sapphire reads in a finished design. White metals such as platinum or 18k white gold will harmonize with the purplish-blue tone and lend a contemporary, luminous field for the star, while 18k yellow or rose gold will create a warmer contrast that can accentuate any subtle purple undertone. A refined halo of small brilliant diamonds can frame the cabochon without competing with the asterism, using melee that follows the oval contour to increase perceived scale and add scintillation around the steady star. Alternatively, subtle pavé shoulders or trapezoid sapphires in a graduated split-shank arrangement can provide support and visual flow without distracting from the cabochon’s central phenomenon. Technical considerations include the height of the bezel lip to protect the dome, a secure seat or collet shaped precisely to the stone’s girdle profile, and an under-gallery that both supports the stone and allows the desired amount of light interaction. Prong settings can be used where exposure to light is prioritized, but they require careful design to secure a rounded cabochon safely, whereas full- or partial-bezel approaches are preferred for everyday wear to reduce the risk of accidental damage.

Custom design and execution are available through The Natural Sapphire Company with a focus on balancing gemstone display, wearer comfort, and long-term durability. Our design process begins with an assessment of how the star registers under typical lighting, followed by CAD renders or hand-sketched proposals demonstrating orientation, bezel height, and accent placement. We can produce wax models or 3D prints for client review to ensure the final proportions respect the stone’s dimensions of 16.11 by 13.96 by 10.43 millimeters and its 10.43 millimeter dome height, allowing adjustments for finger size or pendant bail clearance. Final finishing includes precision setting to maintain the excellent polish of the cabochon, and practical recommendations such as slightly recessed seats, protective shoulders, or shock-absorbing undergalleries for high-wear designs. Care guidance is provided with each commission, advising gentle cleaning with mild soapy water, avoidance of harsh ultrasonic cleaners due to the presence of silk inclusions, and periodic inspection of the setting to ensure ongoing security. For clients seeking a distinctive, wearable piece that showcases a natural, untreated Ceylon star sapphire, our studio at The Natural Sapphire Company offers technical expertise and bespoke design options tailored to the gem’s optical character and the wearer’s lifestyle.