4.69 Ct. Spinel from Tanzania

This 4.69 carat radiant shape spinel measures 10.99 x 7.91 x 5.88 millimeters, yielding a calculated depth percentage of approximately 62.2 percent, dimensions that fall within the ideal range for balanced light return in a rectangular radiant profile. The stone displays a vivid bluish purple hue with even saturation and strong color intensity across the table and pavilion, and it is transparent with a clarity grade of slightly included at eye level. The polish is excellent, which maximizes surface luster and allows the internal brilliance of the spinel to read cleanly in hand. This specimen is untreated, with no enhancement, and is of Tanzanian origin, attributes that are increasingly sought after by collectors and connoisseurs who prioritize natural color and provenance. Physically the spinel offers the practical benefits expected of natural spinel, including a refractive index around 1.718, a specific gravity near 3.60, and a Mohs hardness of about 8, characteristics that support everyday wearability in rings and other wearable jewelry.

The radiant cut on this stone is executed to emphasize both depth and fire, combining trimmed corners and a pavilion architecture that alternates modified brilliant and step facets to produce a lively pattern of scintillation. The crown presents a series of well proportioned star and kite facets that contribute to a strong return of white light, while the pavilion facets are arranged to channel color and flash toward the viewer, enhancing the bluish purple tone without creating excessive windowing. Facet junctions are crisp, which, together with the excellent polish, ensures high contrast between light and dark areas, and the symmetry is consistent across the girdle axis so that the table reflects a stable eye pattern when rotated. Because spinel is singly refractive and shows negligible pleochroism, color stability is maintained under varying angles and lighting, which is an advantage when designing settings intended to show an even face up color. The slight inclusions noted at eye level are localized and do not interfere with the main facet planes, they serve as natural identifiers of an untreated gem and do not materially detract from the gem’s overall optical performance.

From a setting and craftsmanship perspective the radiant outline and clipped corners inform many practical design decisions, and at The Natural Gemstone Company we recommend protecting the delicate corner points with secure prong architecture or precisely fitted bezels. A four or six prong setting with small reinforced corner prongs will guard the corners while still exposing the table for maximum brilliance, whereas a custom bezel can offer edge protection with a contemporary aesthetic, the thickness of the bezel must be calibrated to avoid masking the stone’s profile and to preserve the pavilion clearance required for ideal light return. For high end mounting techniques consider a hand fabricated seat that follows the exact pavilion angle, laser soldered and finished by bench jewelers to maintain perfect symmetry and alignment, micro pave or scalloped gallery work can be engineered to enhance side light without introducing stress points, and in ring applications a low profile head with a secured seat will reduce leverage on the girdle while enabling comfortable daily wear. When setting in platinum or 18 karat gold, attention to thermal and mechanical properties during soldering and stone setting is essential, and we advise final inspection under 10x magnification to confirm prong integrity and polish continuity.

When designing a custom piece to complement this bluish purple spinel consider both color theory and optical interaction, white diamonds are the most recurrent choice, a halo of small brilliant cut melee diamonds will increase perceived size, provide contrast, and intensify the spinel’s color through juxtaposition of pure white light. For a vibrant contrast pairing, intense green gems like tsavorite garnet or demantoid garnet will create a striking complementary color relationship with purple, the warm undertone of an 18 karat yellow gold mounting will further enrich the blue violet, while platinum or white gold will emphasize cooler blue notes. For an analogous palette, consider pairing with pink sapphires or light purplish amethysts to create a soft graduated color field, or integrate small baguette or tapered baguette sapphires in cornflower blue to add structured geometry and directional sparkle. In three stone designs, two flanking trapezoid diamonds or matched trillion cut sapphires will maintain a clear visual axis and support the radiant center gem without overwhelming it. For statement pendants or brooches, combining the spinel with a single Paraiba style tourmaline or a vivid orange garnet will generate exceptional visual contrast and dynamic color shifting under different lights. Each pairing should account for refractive indices and hardness values so that polishing and setting techniques are compatible, and at The Natural Gemstone Company our design consultations include mockups that simulate metal choice, halo scale, and prong geometry to ensure the final piece maximizes brilliance, secures the stone, and achieves the intended color relationship.