0.66 Ct. Orangish Brown Sapphire from Tanzania

This 0.66 carat cushion shape orangish brown sapphire from Tanzania presents precise proportions and gemological transparency that will appeal to the discerning collector, The Natural Sapphire Company offers this stone as an untreated example of natural corundum. The stone measures 5.18 by 5.01 by 2.79 millimeters, producing an average depth of approximately 54.8 percent which sits squarely in the optimal range for a cushion to balance face up color saturation and light return. The mixed brilliant cut employs a brilliant style crown with modified star and upper girdle facets and a step influenced pavilion that retains color while maximizing scintillation, the exact facet geometry producing lively pinpoint flashes and broad satiny flashes under movement. Clarity is assessed as very slightly included at eye level, a grade that indicates only minimal internal features that do not detract from overall appearance, and the polish is excellent, providing crisp facet junctions and clean facet reflections. The sapphire is reported without enhancement, untreated, confirming that the intense color is wholly natural and representative of its Tanzanian pegmatitic host, and standard gemological properties of corundum apply with a refractive index near 1.76, specific gravity near 4.00, and Mohs hardness of nine which combine to make it durable for everyday wear when properly set.

Color in this 0.66 carat cushion is intense, a precise orangish brown that reads warm and rich under daylight and incandescent lighting, the hue balancing orange warmth with brown stability to create a sophisticated tone that photographs well while remaining more nuanced in hand. The mixed brilliant cut is deliberately chosen to modulate face up color, the moderately sized table preserving depth of tone while the crown facet angles contribute to dispersion and lively brilliance, the step influenced pavilion providing controlled light leakage to prevent the face up from appearing overly dark. Pleochroic effects are present as they are in most sapphires, with slightly varying proportions of orange and brown visible when the stone is rotated between crystal axes, a characteristic that enhances perceived life and movement rather than detracting from uniformity. Trace element chemistry typical of orangish brown sapphires involves iron and other transition metals, and the combination of these elements with the cut and proportions results in a vivid color intensity that remains stable under varied lighting, a trait particularly valued by connoisseurs seeking a natural, saturated tone without synthetic modification.

Internal features in this stone act as a fingerprint of its natural formation and add to the gemological story and character of the piece rather than serving as flaws to be erased, the very slightly included clarity grade indicating small but identifiable features at eye level. Observed inclusions include minute pinpoint crystals, very fine needle like inclusions consistent with early growth phases, faint liquid and gas two phase inclusions, and soft growth zoning that records changes in the local chemistry of the crystallization environment, each of these features being useful for origin verification and long term identification. These internal markers are stable, and because the sapphire is untreated, they remain unchanged over time, allowing a buyer to trace provenance and resist untreated gem confusion in the marketplace, The Natural Sapphire Company documents these diagnostic features in our reports to support future certification and resale. From a practical perspective the inclusions contribute subtle texture to the face up appearance, producing delicate silk like veiling in selected viewing angles which enhances depth and richness without compromising durability, careful mounting with protective bezel or prong architecture will preserve the stone and allow its intense orangish brown color and natural internal character to be enjoyed for generations.