3.27 Ct. Cobalt Spinel from Tanzania

This cobalt spinel is a superb example of a rare, naturally blue spinel, offered by The Natural Gemstone Company. It weighs 3.27 carats, and is fashioned into a cushion shape with dimensions of 9.86 by 7.86 by 4.85 millimeters. The cutting style is a mixed brilliant cut, chosen to balance table size and pavilion faceting so as to maximize light return and apparent depth for this particular material. Color is described as medium intense, a hue that sits attractively between the lighter pastel blues and the deepest velvets, and this intensity allows the stone to show a strong, saturated blue in both direct and diffused light. Clarity has been graded as slightly included when evaluated at eye level, meaning that small natural inclusions are present but do not materially obscure the gem or compromise its overall transparency. The polish is excellent, which enhances brilliance and contributes to a clean surface appearance that reduces the visual impact of internal features. The stone is reported as no enhancement, and it is of Tanzanian origin, with a certification accompanying the piece that documents its identity as a cobalt-bearing blue spinel.

From a gemological and aesthetic standpoint, several attributes of this specimen make it noteworthy to educated buyers. Cobalt spinel is distinct from traditional blue corundum in its chemistry and optical response, the vivid blue being imparted by trace cobalt substituting in the spinel lattice rather than by iron or titanium as in some other blue gems. The cushion outline and the mixed brilliant faceting provide a classical silhouette while adding modern scintillation, and the dimensions present a generous face-up area for a 3.27 carat weight. Slight inclusions are common in natural spinel, and in this instance they are minor enough to preserve strong transparency and attractive light performance. The lack of any enhancement, such as heat treatment or dyeing, is particularly important, because untreated, naturally saturated blue spinel of Tanzanian origin commands premium interest among connoisseurs who prioritize natural material and documented provenance. The excellent polish reduces light leakage and aids the stone in appearing larger and livelier than less well-finished equivalents.

Regarding investment potential, this cobalt spinel displays many of the characteristics collectors and investors look for when considering colored gemstones as an alternative asset. Supply of cobalt-bearing blue spinel is inherently limited, because occurrences that produce this specific trace element combination are rare, and mining and export from Tanzanian localities are subject to geological and regulatory constraints that restrict long term, predictable supply. At the same time, market recognition of spinel as a collector and investor category has increased over the past two decades, as buyers seek alternatives to traditional corundum and diamond markets. Key investment-positive features of this stone include its untreated status, a meaningful carat weight above three carats, an attractive and marketable cushion cut, and clear documentation from a reputable source. Stones that combine scarcity, aesthetic appeal, and full disclosure of origin and treatment history tend to show stronger price resilience, and in many cases appreciation, particularly when held over a medium to long term horizon. That said, gemstone markets are not immune to cyclical demand and liquidity considerations, and past performance of any category is not a guarantee of future returns.

For buyers considering this cobalt spinel as either a personal jewel or an investment piece, practical advice is to secure independent laboratory documentation if you require it, to insure the stone for its replacement value, and to maintain full provenance records supplied by The Natural Gemstone Company. Proper setting that protects the girdle and pavilion, and professional cleaning and care, will preserve visual appeal and resale potential. Investors should also consider that the most robust appreciation scenarios occur when stones are both rare and highly desirable in the market, and this specimen’s combination of medium intense cobalt blue, excellent polish, natural origin from Tanzania, and absence of enhancement positions it favorably. If you would like the certification details, magnified images, or assistance with a bespoke setting, The Natural Gemstone Company can provide the supporting paperwork and personalized service to help ensure this gemstone meets both aesthetic and investment criteria.