1.70 Ct. Tanzanite from Tanzania

One transparent 1.70 carat round violetish blue tanzanite with precise dimensions of 7.52 x 7.42 x 4.61 millimeters is presented by The Natural Gemstone Company. The gem is fashioned in a mixed brilliant cut, combining a faceted crown and pavilion geometry that preserves weight while optimizing light return. Clarity has been evaluated at eye level as very very slightly included, yielding an essentially eye-clean appearance that enhances visual purity and sparkle. Color is described as intense, a saturated violetish blue that reads clearly across photographs and in hand, and the stone exhibits an excellent polish that sharpens facet junctions and contributes to crisp scintillation. Importantly, this tanzanite bears no enhancement, a characteristic of growing significance given how commonly heat treatment is applied to zoisite to intensify blue tones. Origin is Tanzania, and the stone’s natural provenance informs both its gemological character and its collectible value.

The mixed brilliant cut has been selected to balance color saturation with luminosity, adapting facet geometry to the tanzanite’s pleochroic nature so that the most desirable blue-violet tones predominate when set. Tanzanite is known for strong pleochroism, with blue, violet, and occasionally warm brownish reflections evident from different viewing angles. The cutter has oriented the rough to maximize the blue-violet face-up color while maintaining near-round symmetry and optimal depth at 4.61 millimeters. At approximately 7.5 millimeters across, the stone occupies a size range that translates to notable presence in a solitaire ring or pendant without compromising wearability. The VVS-grade clarity, combined with the excellent polish, allows light to travel through clean facets with minimal internal interruption, enhancing both brilliance and the perception of depth in the intense color field.

When compared to lab-grown gemstones, natural tanzanite offers several distinct advantages that are especially relevant to collectors, designers, and clients seeking enduring value. Natural stones reflect a geological history and geographic specificity, in this case formation within the metamorphic environments of Tanzania, factors that contribute to rarity and provenance-based appeal. Inclusions and growth features present in natural gems act as unique identifiers or fingerprints that support long-term traceability and authenticity assessments, whereas lab-grown equivalents tend to be more uniform and lack individualized growth signatures. The absence of enhancement in this specimen further amplifies its desirability because natural, untreated vibrant color is less common and often commands a premium in secondary markets. From an investment perspective natural, untreated gems with documented origin and strong gemological characteristics typically retain or appreciate value more reliably than synthetic counterparts, which are plentiful and command a different pricing structure. Additionally, many clients place intrinsic or sentimental value on a material that is the product of natural geological processes, an attribute that laboratory production cannot replicate.

For practical use and care, the physical properties of tanzanite warrant consideration when planning setting and wear. Tanzanite has a relative hardness that is adequate for everyday jewelry when properly protected, but it does have distinct cleavage and can be vulnerable to sharp blows or sudden thermal shocks, and therefore should be set with protective bezel or secure prongs for rings subject to frequent wear. Cleaning is best performed with warm soapy water and a soft brush, avoiding steam or ultrasonic cleaners which can risk damage in some cases. For bespoke settings our gemologists at The Natural Gemstone Company can advise on mounting styles that preserve the stone’s optical performance while minimizing exposure to impact. Each gemstone we offer is described with precise measurements, cut and clarity grading, color intensity assessment, and disclosure of enhancements or lack thereof, so clients can make informed choices. This 1.70 carat, untreated, Tanzanian tanzanite combines saturated natural color, excellent polish, and high clarity in a size and cut that is well suited to refined jewelry designs, and stands as an example of the distinctive attributes natural gemstones provide over laboratory-grown alternatives.