11.34 Ct. Cabochon Tourmaline from Tanzania

This exceptional GIA certified purplish pink tourmaline from Tanzania presents as an 11.34 carat oval cabochon, with precise dimensions of 12.77 by 11.13 by 10.32 millimeters, and a transparency that allows for a clear reading of internal features when viewed under transmitted light. The cabochon cut embraces a classical high domed profile, executed to emphasize color saturation and internal optical effects rather than faceted scintillation, and the cutter has oriented the dome to lie parallel to the optic axis of the crystal to maximize uniformity of the purplish pink hue. The clarity is graded slightly included at eye level, which is consistent with natural tourmaline habit, and the inclusions are coherent with linear growth features and occasional fluid or phase inclusions that contribute to internal texture without materially disrupting color transmission. The polish is excellent, producing a smooth, glass like surface that minimizes light scatter and enhances the stone to metal interface in finished jewelry. The material has been heat treated to refine tone and reduce brownish overtones, a standard and fully disclosed enhancement in the trade, and the GIA report documents the treatment and origin, providing laboratory verification that supports provenance and market value.

Optically this cabochon behaves in ways that reward deliberate lighting, and understanding those responses allows the purchaser to anticipate how the stone will perform in different real world situations. In neutral daylight, particularly in northern indirect daylight or color balanced LED lighting around 5000 to 6500 Kelvin, the stone reveals its primary purplish pink axis with vivid color intensity, showing a balanced blend of pink and subtle violet components due to tourmaline pleochroism. Under warm incandescent or halogen illumination, the heat enhanced pink shifts towards a richer warm pink to purplish red, the increased red component becoming more prominent and creating the impression of greater depth. Cool white LEDs and fluorescent sources tend to emphasize the violet component, making the stone read slightly cooler and more toward a purplish tone, particularly when observed at oblique angles. Because the piece is a cabochon, it can also display a directional highlight or asterism like a thin starline when linear inclusions are present and when the dome is cut to intersect them, and viewers will notice a bright, concentrated band of reflected light traversing the dome under a single point source, an effect that can be used intentionally to create a cat eye or star character in jewelry. The gem’s refractive index range, approximately 1.62 to 1.64 for tourmaline, combined with a specific gravity near 3.06, yields a strong color saturation in this weight and dimension, and the moderate hardness near seven to seven and a half on the Mohs scale provides durability suitable for rings and pendants with appropriate protective settings.

From a craftsmanship and setting perspective, the cabochon form of this purplish pink tourmaline invites mounting designs that either protect the profile or maximize light interaction, depending on the client’s priorities. A bezel setting with a low to medium rim will protect the rim and dome and will present the vivid color as a continuous field, ideal for everyday wear, while an open back or partially open gallery will permit transmitted light to enter the base and enhance internal glow for more dramatic appearance in pendants or earrings. For rings where the cabochon’s optical effects are a focal point, a slightly elevated collet that allows raking light to travel across the dome will showcase the starline or chatoyancy, and choosing rose gold or warm yellow gold will harmonize with the warm reds in incandescent light, whereas white gold or platinum will create a crisp contrast that accentuates the violet shift under cool lighting. Routine care should include gentle warm soapy water and a soft brush, avoiding harsh ultrasonic cleaning methods because of the documented heat enhancement and natural inclusions, and The Natural Gemstone Company will supply the GIA certificate with full disclosure of treatment and origin to accompany the gem. This purplish pink tourmaline offers a combination of substantial carat weight, museum worthy polish, credible laboratory documentation, and versatile optical personality, making it an excellent candidate for a signature ring or pendant that will present differently but attractively under daylight, incandescent, LED, and directional lighting conditions.