0.32 Ct. Alexandrite from Tanzania

This transparent alexandrite presented by The Natural Gemstone Company is a precisely measured and expertly finished gem, weighing 0.32 carat, with an oval outline and exact dimensions of 4.66 millimeters by 3.61 millimeters by 2.56 millimeters. The stone exhibits a distinctive color change from bluish green in fluorescent light to a reddish purple in incandescent illumination, a hallmark of chromium bearing chrysoberyl. The cutting style is a mixed brilliant, combining a faceted brilliant crown with a proportionally tuned pavilion intended to maximize both scintillation and the alexandrite color shift. The clarity is graded as very slightly included at eye level, indicating minimal internal features that do not detract from overall transparency and light performance. Color intensity is assessed as medium, which in alexandrite often delivers the most balanced expression of the green and red color axes, and the polish has been executed to an excellent standard, with crisp facet junctions and a smooth, reflective surface. There has been no enhancement to this stone, and its documented origin is Tanzania, which informs both its geological pedigree and its specific chromophore characteristics.

From a cutting and optical engineering perspective, this piece demonstrates careful attention to proportion and symmetry. The length to width ratio is approximately 1.29 to 1, yielding a classic, slightly elongated oval that is versatile for a variety of mounting designs while preserving a broad table area for color interplay. The measured depth of 2.56 millimeters produces a depth to average diameter ratio of approximately 61.9 percent, a depth range that supports efficient light return in a mixed brilliant configuration while permitting the internal dispersion and color zoning to remain visible. The mixed brilliant approach, with a well calibrated crown angle and a pavilion composed of modified facets, is specifically chosen to control the balance between brilliance and the directional color phenomenon that defines alexandrite. Facet junctions have been finished to ensure minimal light leakage and optimal contrast, enhancing both face up appearance and the dynamic color change when the gem is moved between different light sources.

Consideration of the gem at the microscopic and atomic levels explains the remarkable chromatic behavior and the reasons this material is prized by connoisseurs. Alexandrite is a chromium bearing variety of chrysoberyl, with a crystalline formula where beryllium, aluminum, and oxygen form a rigid lattice into which trace chromium ions can substitute. Millions of years ago, in the high grade metamorphic environment that now forms parts of Tanzania, tectonic pressures and elevated temperatures mobilized fluids rich in beryllium and aluminum. Chromium sourced from adjacent ultramafic slivers or from localized metasomatic activity became incorporated during crystal growth, producing the precise balance of chromophores required for color change. The crystalline lattice of chrysoberyl is highly durable, resistant to strain, and capable of accommodating small amounts of substitutional elements without structural collapse, which is why the stone remains transparent and exhibits the clear color shift observed. Over geologic time, these crystals were exhumed, transported by erosional processes, and concentrated in small pockets where gem quality material could be recovered, subsequently sorted, and fashioned into the polished gem you see.

For the buyer who values both geological narrative and technical craftsmanship, this alexandrite from The Natural Gemstone Company represents a synthesis of natural rarity and human precision. The medium color intensity and very slightly included clarity make it suitable for a fine bezel or prong setting that allows the stone to breathe and reveal its color change, while the mixed brilliant cut maintains lively scintillation in everyday wear. Because there are no enhancements, the stone’s optical behavior is entirely natural, and the Tanzanian origin adds provenance that is relevant to collectors and gemmologists alike. Setting recommendations include an open gallery to permit variable light access, and a mounting that protects but does not overly enclose the pavilion, preserving the light paths that produce the blue green and red purple transitions. Meticulous polishing and facet alignment ensure this 0.32 carat alexandrite will perform consistently under variable lighting conditions, and it is offered with the confidence in sourcing and expertise associated with The Natural Gemstone Company.