3.27 Ct. Cabochon Alexandrite from Russia

This translucent cabochon alexandrite from Russia weighs 3.27 carats, and measures 10.99 by 7.77 by 3.73 millimeters, oval in shape, and finished to an excellent polish. The piece exhibits a greenish tone under fluorescent and daylight conditions, and a purplish tone under incandescent lighting, reflecting the characteristic alexandrite color change that defines the variety. Clarity is graded as slightly included when viewed at eye level, a common attribute in natural alexandrites that can contribute to a soft internal glow without compromising the stone's overall appeal. There has been no enhancement applied to this gem, and its intense color saturation and the careful cabochon cut preserve a pure, undisturbed presentation of the material. The Natural Gemstone Company provides this description to document the gem's natural origin, cut, weight, dimensions, and condition.

The optical behavior and apparent sparkle of this alexandrite arise directly from its crystal chemistry and internal structure. Alexandrite is a chromium bearing variety of chrysoberyl with an orthorhombic crystal lattice, and chromium substituting into the aluminum sites produces strong, narrow absorption bands in the visible spectrum. Those bands are responsible for the dramatic shift from green to purplish red as the spectral composition of the illumination changes, and they also influence how light is transmitted and internally reflected within the stone. In addition, chrysoberyl has a relatively high refractive index, which increases the amount of light that is both retained and redirected inside the gem. When a cabochon is formed from such material, the smooth domed surface does not create the facet to facet scintillation of a brilliant cut, yet it does encourage broad, luminous reflections that produce a distinctive internal radiance. Slight inclusions and internal growth features can act as microscale reflectors and diffusers, breaking and scattering light so that the gem appears to glow from within rather than merely sparkle from surface facets. The combined effects of selective absorption due to chromium, elevated refractive properties of chrysoberyl, and the internal scattering by natural inclusions yield a type of optical response that is unique to alexandrite and difficult to replicate in other gem species.

The choice of a cabochon cut for this 3.27 carat Russian alexandrite accentuates its most prized optical characteristics. A faceted stone emphasizes sharp, point source reflections and contrasty scintillation, while a well executed cabochon emphasizes color depth, subtle luminosity, and the integrity of the color change. The excellent polish maximizes surface luster, allowing the dome to act as a smooth window through which the internal light play can be observed, and it preserves the continuity of the color shift across viewing angles and lighting types. For practical considerations in jewelry design, the dimensions and weight make this stone suitable for a variety of settings where the color change can be appreciated, such as rings with open side galleries, pendants with unobstructed viewing, or brooches that allow frequent observation under varying light. Because the gem is natural, untreated, and of Russian origin, it presents a historically recognized material provenance that many collectors and connoisseurs value for its classic alexandrite qualities. The Natural Gemstone Company documents these attributes to aid in accurate evaluation and to present an objective account of how the stone's intrinsic structure and finish combine to create a luminous presence and a sparkle that is distinct among gemstones.