1.50 Ct. Color Change Sapphire from Ceylon (Sri Lanka)

This exceptional transparent 1.50 carat color change sapphire is an outstanding example of natural Ceylon gem material, presented in a classic emerald cut and measuring 6.95 by 5.65 by 3.92 millimeters. The gem carries a clarity grade of very slightly included, evaluated at eye level, which in practical terms means the stone is remarkably clean to the unaided eye, permitting superb light transmission and crisp facet reflections. The polish is excellent, and importantly this sapphire has received no enhancement, preserving the integrity of its natural color and internal structure. At The Natural Sapphire Company we source and present material of this quality with full disclosure, so an educated buyer can be confident in both the provenance and the unaltered nature of this stone.

From a gemological perspective this sapphire is composed of corundum, aluminum oxide with the chemical formula Al2O3, a dense and durable crystal that rates nine on the Mohs scale of hardness. Corundum has a refractive index around 1.762 to 1.770 and a modest birefringence, properties that govern how light slows and splits as it passes through the crystal lattice. In combination with the stone s very slightly included clarity and excellent polish, these optical constants create strong internal reflection and well defined facet contrasts. Color change behavior in sapphires is commonly caused by trace elemental activators such as vanadium, and sometimes iron and titanium, which alter the wavelengths of light that are preferentially absorbed under different lighting conditions. The vivid color intensity of this Ceylon stone amplifies that effect, so the gem can shift from a rich bluish violet in fluorescent or daylight to a more saturated purple under incandescent illumination. This dynamic response to illumination is a hallmark of the rare color change variety, and when paired with transparent material it produces a depth of color that is both lively and complex.

The emerald cut chosen for this sapphire is a thoughtful pairing of shape and material that enhances the gem s unique optical personality. The stepped pavilion and broad table create a hall of mirrors effect, emphasizing color and clarity rather than the sparkling pinfire seen in mixed cuts. Because this stone has very clean transparency and excellent polish, the step facets act like precise mirrors, yielding broad flashes of saturated hue and strong color contrast as the gem is moved through light. The high refractive index of corundum ensures that those flashes are intense, and the combination of pleochroism and trace element absorption means the flashes will display distinct shifts in tone and temperature depending on lighting. For the educated buyer this means an object that is at once consistent in color intensity, and also dramatically responsive, turning the act of viewing into a sensory experience. The lack of enhancement further increases desirability and investment value, since the color and structure are entirely natural. When set in a well proportioned mounting the stone will display its color change to advantage, while its excellent hardness and polish will maintain finish and facet crispness over time. At The Natural Sapphire Company we are available to discuss settings and mounting styles that will showcase the color change to its fullest, and to provide additional documentation on origin and grading for collectors and connoisseurs.