11.45 Ct. Cabochon Tanzanite from Tanzania

This piece is an 11.45 carat translucent violet tanzanite presented in an oval outline, with measurements of 14.72 x 10.66 x 8.27 mm, cut as a traditional cabochon. The cutting style is a high dome oval cabochon, executed to maximize color saturation and transmission rather than faceted brilliance. Clarity is graded included at eye level, which means internal features are visible without magnification and participate in the stone's overall character. The color is described as vivid in intensity, offering a strong, saturated violet that is evenly distributed across the face of the gem. The surface condition is excellent, with a uniformly applied polish that provides a clean reflective luster across the dome, enhancing the apparent depth of color. This tanzanite has been heat treated, a standard and stable enhancement for zoisite from Tanzania, applied to remove brownish overtones and to intensify the blue violet hues. The provenance is Tanzania, the primary commercial source for gem quality tanzanite, and the piece is offered by The Natural Gemstone Company.

From a cutting and lapidary perspective the cabochon approach was selected to emphasize body color and pleochroic display rather than to maximize faceted sparkle. The cutter oriented the rough to favor the violet axis, resulting in a dominant violet face up presentation with minor blue flashes under angled light. The dome profile is balanced for both aesthetics and wearability, with sufficient height to show depth yet low enough to sit securely in bezel settings. The excellent polish indicates that the final stages included progressively finer abrasives and a felt or leather lap with cerium or diamond polish, yielding a smooth, mirror like surface for optimal light entry and return. Internal inclusions remain visible but have been positioned and trimmed to reduce any disruptive reflections or internal stress concentrations. The translucency allows light to penetrate and diffuse across the dome, creating a soft, velvety appearance rather than sharp scintillation, which is characteristic of well executed cabochon tanzanite.

On the gemological side this specimen belongs to the zoisite group and displays pronounced pleochroism, a key optical characteristic that must be considered when setting and viewing the stone. Typical refractive index values for tanzanite fall within the ranges of approximately 1.69 to 1.71, with limited dispersion and a birefringence that can be detected with sensitive instruments. Specific gravity for zoisite based tanzanite is near 3.35. Hardness is moderate, generally reported between 6 and 7 on the Mohs scale, which necessitates protective mounting in jewelry intended for frequent wear. The included clarity grade signifies that internal needle like crystals, fine healed fissures, or pinpoint mineral inclusions are present, and these features can contribute to the character and identification of the material while occasionally affecting light transmission. Heat treatment in tanzanite is an established practice that alters color by reducing brown or olive components and enhancing blue and violet tones, and when properly executed the result is stable under normal wearing conditions. All of these technical attributes combine to explain the visual performance of this cabochon, namely the saturated violet face up color that remains intense under direct and diffused lighting.

For application in jewelry and for design considerations the dimensions and cabochon cut of this 11.45 carat tanzanite make it particularly suitable for a center stone in a pendant, a statement ring with protective bezel, or custom designs where the dome can be showcased without risk of abrasion. Bezel settings or low profile frames are recommended to protect the girdle and to support the cabochon dome, especially given the moderate hardness and the presence of eye visible inclusions. Orientation during setting should preserve the pleochroic axis that yields the most desirable violet face up color, and jewelers should avoid excessively high prongs that could stress the stone during mounting. Cleaning should be done with mild soap and warm water and a soft brush, avoiding steam cleaners and ultrasonic systems when significant inclusions or healed fractures are present, since those cleaning methods can exacerbate internal weaknesses. This tanzanite represents a combination of substantial carat weight, vivid color and careful cabochon cutting, making it a collectible piece for connoisseurs and designers who prioritize color saturation and natural character. The Natural Gemstone Company is pleased to present this Tanzanian violet tanzanite as a specimen that demonstrates both lapidary skill and the classic optical properties of fine tanzanite.