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

This specimen is a transparent 16.78 carat oval blue sapphire, presented in a cabochon cut with dimensions of 15.06 x 10.12 x 10.11 mm. The pavilion and dome have been polished to an excellent finish, producing a reflective, glass-like surface that amplifies the stone's visual depth. The gem is graded as very slightly included when evaluated at eye level, indicating minimal visible inclusions that do not significantly interrupt its homogeneity or surface appearance. Color intensity is described as dark, and the stone has been heat treated, a common and stable enhancement used to optimize body color and clarity. Origin is Ceylon, Sri Lanka, a provenance long associated with sapphires that display lively blue hues and a generally bright, clean appearance. The oval proportions sit comfortably between length and width, making the stone well suited for a central ring or pendant setting that showcases its substantial carat weight and smooth domed profile.

In tone and hue this Ceylon cabochon presents as a deep, saturated blue with cool, slightly inky undertones, a profile that differs from the lighter, cornflower blues often associated with classic Ceylon pieces. Compared with Kashmir sapphires, which typically have a distinct velvety cornflower blue character with a medium to slightly strong tone and a soft, silk-like diffusion, this stone is decidedly darker and less silvery in appearance. Against renowned Burmese sapphires, which frequently show a rich, vivid royal blue with intense saturation and a somewhat warmer, more luminous quality, the present gem reads cooler and deeper, leaning toward an indigo-leaning blue rather than the brisk, vivid blues of top Burmese material. This comparison emphasizes that while the stone is Ceylon in origin, its dark intensity gives it a presence that sits between traditional Sri Lankan brightness and the deeper, more saturated appearance commonly prized in Burmese examples.

A second comparative perspective highlights how this sapphire relates to other geographic expressions of blue corundum. Australian sapphires and many commercial dark blues from other locales can appear very inky or near-black in heavier tones, often sacrificing visible internal life for surface depth; the present cabochon retains internal depth and translucency even at its dark intensity, avoiding a purely opaque, dead-black look. Montana sapphires and certain Madagascar stones often carry greener or teal-inflected hues, whereas this gem maintains a predominantly pure blue hue with only minor cool undertones, reinforcing its identity as a blue rather than a blue-green sapphire. The cabochon cut here accentuates the stone’s depth of color and internal flashes when oriented to light, providing a different aesthetic than a faceted stone of similar hue, and making it especially suitable for designs where color mass and a smooth reflective dome are the primary considerations.

From a practical and connoisseurship standpoint, the combination of size, cut, and origin makes this a noteworthy example for collectors and designers. At 16.78 carats, the sapphire carries substantial presence and will translate to a bold center stone in domestic jewelry, with the cabochon form lending itself to secure settings such as a bezel or low-profile prong work that protect the rounded surface while permitting light to articulate the internal depth. The excellent polish supports a refined appearance under loupe and naked-eye viewing, while the very slightly included clarity grade indicates that any natural features are minor and do not compete with the overall uniformity of color. The Natural Sapphire Company documents the stone as heat treated, a stable and accepted enhancement that enhances visual qualities without obscuring origin or natural character. This Ceylon cabochon offers a deep, cool blue expression that will appeal to those who favor a saturated, contemplative blue with the provenance and craftsmanship expectations associated with fine Sri Lankan sapphires.