3.27 Ct. Purplish Blue Cobalt Spinel from Tanzania

This transparent cobalt spinel weighs 3.27 carats and presents a cushion shape with precise dimensions of 9.86 by 7.86 by 4.85 mm, making it suitable for a variety of fine jewelry settings. The stone is faceted with a mixed brilliant cut that balances large pavilion facets and a well proportioned crown to maximize light return and visual depth. Color is a purplish blue of medium intensity, created by the presence of cobalt within the crystal lattice, and the stone displays an even hue distribution across the table and crown. Clarity has been evaluated as slightly included at eye level, and the gem exhibits an excellent polish that enhances surface luster and facet definition. The piece is natural, originating from Tanzania, and it has not undergone any enhancements, a factor that contributes to its stable, inherent character and predictable behavior in jewelry.

From a durability perspective this cobalt spinel is well suited to daily wear. Spinel rates 8 on the Mohs scale, which provides considerable resistance to scratching under normal wear conditions, and the species is known for its lack of true cleavage, which improves its toughness and reduces the likelihood of splitting under impact. The excellent polish and robust faceting further protect the surface by minimizing microabrasion on the most exposed planes. Because the gem is unenhanced, it retains the original physical properties imparted at formation, including thermal stability and resistance to routine environmental factors that can affect treated stones. For daily use in rings and bracelets, a secure setting is recommended, with either a protective bezel or a well designed prong arrangement that supports the pillow shaped corners and protects the girdle. Thoughtful mounting that shelters the pavilion and corners will preserve both the aesthetic and the structural integrity of the gem over time.

Beyond hardness and toughness, several practical attributes favor this stone for everyday jewelry. The mixed brilliant cut yields lively scintillation and a pleasing balance between sparkle and color saturation, attributes that maintain visual appeal under varied lighting conditions. Slight inclusions noted at eye level are natural characteristics of mined material, they do not compromise the stone’s strength, and they add to the individuality and provenance associated with natural Tanzanian spinel. The measured dimensions allow jewelers to estimate bezel and seat sizes accurately for rings and pendants, and the moderate depth of 4.85 mm supports secure setting without excessive elevation. The Natural Gemstone Company presents this cobalt spinel as a reliable choice for clients seeking a durable, attractive natural stone that combines excellent polish, a stable, unenhanced origin, and the mechanical properties needed for regular wear. Care for the stone with gentle cleaning using warm water, mild soap, and a soft brush to maintain luster, and when considering repairs or resizing choose experienced setters who will respect the cushion profile and protect the girdle and corners during work.