0.51 Ct. Alexandrite from Brazil

This 0.51 carat marquise alexandrite presents a distinctive combination of proportions and optical properties, the hallmark of quality material offered by The Natural Gemstone Company. The stone measures 8.86 by 3.89 by 2.23 millimeters, with a refined marquise silhouette that reads elongated and elegant when set. It is transparent, with a clarity grading described as very slightly included as evaluated at eye level, meaning internal features are minimal and do not disrupt the overall visual purity. The cutting style is a mixed brilliant cut, finished with an excellent polish, and the stone exhibits intense color intensity in both lighting conditions. The material is untreated, with no enhancement, and the documented origin is Brazil, a locality known for producing alexandrite specimens that display strong, clean color change and well formed crystals.

The unmatched sparkle of this alexandrite arises from the intrinsic interaction between its atomic structure and the precise geometry of the cut. Chrysoberyl, the species to which alexandrite belongs, has a relatively high refractive index and measurable dispersion, properties that determine how aggressively light is bent and separated into spectral components as it enters and exits the crystal. In practical terms, these parameters create a pronounced return of light to the viewer, producing lively brilliance and scintillation. The mixed brilliant faceting strategy employed here combines large table and crown facets with a series of smaller pavilion facets, an arrangement that optimizes both flashes of white light and colored light return. The marquise outline further concentrates these effects along the length of the stone, generating a rhythmic play of light that alternates between bright flashes and deeper, colored flashes depending on the viewing angle and the lighting environment.

Color change behavior in alexandrite amplifies the perceived sparkle because the stone does not merely reflect light, it redistributes it between different parts of the visible spectrum. Trace chromium and related transition elements within the chrysoberyl lattice selectively absorb and transmit different wavelengths under varying spectral conditions, so under daylight or fluorescent lighting the gem presents a green to bluish green profile, while under incandescent or warmer light it shifts toward purplish red. That dynamic redistribution accentuates facet contrast, since the facets that return cooler wavelengths will read differently against those returning warmer wavelengths, increasing the sense of depth and motion. The very slightly included clarity grade ensures that light can traverse the body without significant scattering from inclusions, maintaining crisp facet contrast. Excellent polish guarantees that facet planes are reflective and uniform, which is essential because even minor lapses in polish can diffuse light and dull scintillation. Together, the material properties and cut geometry create a level of optical performance that is both lively and nuanced.

From a setting and use perspective, this marquise alexandrite offers practical advantages that support its visual impact over time. The slender profile and measured length to width relationship make the stone versatile for a range of ring designs, as well as for pendants where its color change can be observed against the skin or clothing. Because the material is natural and untreated, the color change and sparkle are inherent characteristics of the crystal, not the result of coatings or laboratory interventions, which ensures stable long term behavior with appropriate care. For optimal presentation, a setting that allows light to enter from the sides and beneath, combined with secure prongs or a low bezel that does not obscure the pointed ends, will preserve the dynamic light performance. The stone is well suited to a bespoke mounting where the orientation of the marquise and the choice of metal can be selected to either emphasize the green aspect under daylight or the purplish red aspect under warmer illumination.

At The Natural Gemstone Company we document provenance and treatment status as part of our standard practice, and we make the material specifications available to support informed design decisions. The combination of a high refractive index, tangible dispersion, mixed brilliant faceting, excellent polish, and a transparent, very slightly included material from Brazil is what gives this alexandrite its particularly compelling sparkle. For clients seeking a gem that offers both technical excellence and an engaging optical personality, this piece represents a natural example of how crystalline structure and expert cutting converge to maximize brilliance and color dynamics. Please contact us for additional images, measurements taken under specific lighting conditions, or advice on settings that will best showcase the stone in wearable form.