0.74 Ct. Greenish Blue Cabochon Sapphire from Montana

This transparent greenish blue sapphire weighs 0.74 carat, with an oval outline measuring 6.28 x 4.90 x 2.12 mm, and it is fashioned as a cabochon. The stone exhibits a very light color intensity with a subtle greenish blue hue that is evenly distributed across the dome, and under close inspection the body color reads as a delicate pastel tone typical of Montana material. Clarity is graded as slightly included at eye level, the inclusions presenting primarily as fine needle and plate features oriented parallel to the basal plane, and these internal characteristics are consistent with natural corundum from this provenance. The polish has been executed to an excellent standard, the surface appearing glassy under direct illumination, and the cabochon demonstrates a clean specular reflection with minimal surface pits or abrasions. The piece has been heat treated, a standard and disclosed enhancement intended to stabilize and subtly improve color uniformity and clarity, and the combination of these attributes yields a gem with a refined and natural aesthetic.

From a lapidary perspective, the cabochon execution emphasizes controlled dome geometry and precision symmetry, the cutter retaining material to balance weight retention and optical performance. The crown dome is at medium height, designed to present a pleasing bullseye when viewed face up while avoiding excessive windowing that can wash out the delicate color. Edge treatment is even and rounded to a consistent girdle profile, which facilitates secure bezel setting and minimizes stress concentration during setting. The preparatory work employed traditional preforming to align the crystal’s pleochroic axes with the long dimension of the oval, thereby maximizing the visible hue and minimizing undesirable color shift when the stone is set. Final polishing was completed using progressively finer diamond pastes and felt laps to achieve the excellent polish noted, and the result is a smooth, high gloss surface that enhances light return and tactile quality. As corundum, the sapphire benefits from a refractive index range and a hardness of nine on the Mohs scale, properties that contribute to crisp light performance and strong wearability in everyday jewelry.

The Montana origin imparts specific character, as sapphires from this region are prized for their pastel and alpine tones, and collectors value the provenance for its geological and aesthetic distinctiveness. The disclosed heat treatment in this example is modest and intended to improve color saturation while preserving the stone’s natural appearance, and the slightly included clarity adds to the gemological story without detracting from its visual appeal when set. For mounting, a low to medium dome cabochon like this performs exceptionally well in bezel and halo bezels that protect the perimeter and provide a visual frame that deepens perceived color, and open back settings on custom pieces can be used selectively to allow light transmission if a brighter face up appearance is desired. At The Natural Sapphire Company we can advise on metal choices and setting profiles that complement the greenish blue tone, for instance warm rose gold for contrast, or platinum for a cooler, contemporary presentation. If you would like further technical details, high resolution images, or consultation on mounting and certification options, please contact The Natural Sapphire Company and we will provide expert guidance tailored to your design and gemological preferences.