1.63 Ct. Bluish Green Cabochon Sapphire from Montana

This Montana sapphire offered by The Natural Sapphire Company is a semi translucent, cabochon cut oval weighing 1.63 carat, with calibrated dimensions of 7.19 x 5.95 x 3.52 mm. The cabochon form presents a smoothly domed crown and a well proportioned depth that reads as a medium profile, a proportion chosen to optimize body color while managing light transmission through the stone. The shape is a classic oval with soft symmetry, and the polished dome provides a broad, continuous surface that emphasizes the bluish green hue. Color grading evaluates the tone as medium, with an intensity described as medium intense, a balance that allows both green and blue wavebands to be appreciated under varied lighting. The stone is semi translucent rather than fully transparent, which creates a softened internal appearance and a gentle diffusion of light that is characteristic of high quality Montana material.

Clarity is graded included when viewed at eye level, and the internal features contribute to the stone character rather than detract from overall appeal. Visible inclusions exhibit as fine internal textures and discrete mineral particles that are typical for Montana sapphires, and these inclusions interact with the cabochon dome to produce zones of light scattering and subtle color zoning. Optical parameters for corundum inform how this material presents, with a refractive index in the established range for sapphire, low birefringence, and a vitreous surface luster on polished areas. The gem shows subdued pleochroic tendencies that cause detectable shifts between blue and green components when the stone is rotated, a behavior that the cutter accounted for when orienting the preform. Heat treatment has been applied, a stable and common enhancement for Montana sapphires, employed to refine hue balance and reduce some of the more reflective silk and particulate concentrations, while preserving the natural semi translucent character.

From a craftsmanship perspective this cabochon demonstrates precise lapidary technique, starting with careful preforming to center the optical axis, followed by progressive wheel cutting to establish an even dome, and finishing with fine abrasives and a final polishing lap to achieve an excellent polish. The dome height is calibrated to avoid windowing, a phenomenon where excessive flatness produces a washed out appearance, and to instead maintain saturation and depth of color. Edge finishing is even, avoiding sharpness that could be a vulnerability during setting. For jewelry applications this sapphire is suited to bezel settings that protect the girdle and anchor the cabochon securely, or to open backed designs that allow ambient light to interact with the stone from behind, enhancing perceived depth for certain mounting styles. Given the semi translucent nature and included clarity grade, a protective setting is advisable for daily wear, and secure mounting will minimize the risk of chipping along the perimeter.

Practical recommendations for collectors and designers are focused on maximizing the stone attributes while acknowledging its treatment and inclusion characteristics. Lighting will alter visual appearance, with cooler daylight revealing bluer notes and warmer incandescent light favoring greener tones, and rotating the stone will reveal the pleochroic shift that is a hallmark of natural corundum. Cleaning is straightforward, using warm water and mild detergent, with ultrasonic and steam cleaning acceptable in many cases but to be used with care depending on the nature of inclusions and the setting. Certification and disclosure are provided by The Natural Sapphire Company, and provenance from Montana is an important attribute for connoisseurs who value the unique geological signatures of American sapphires. For bespoke projects our lapidary team can advise on bezel dimensions, back settings, and complementary accent stones to create a balanced design that respects the cabochon form and highlights the medium intense bluish green tone.