7.91 Ct. Chrysoberyl from Ceylon (Sri Lanka)

This specimen is a transparent 7.91 carat oval yellowish green chrysoberyl, with dimensions 16.58 by 10.71 by 5.09 millimeters, cut in a mixed brilliant configuration, and originating from Ceylon Sri Lanka. The material is untreated, with no enhancement, and it exhibits intense color saturation paired with excellent polish. Clarity has been graded as very slightly included when examined at eye level, meaning the inclusions are minimal and do not materially disrupt the passage of light or the visual field of the face up view. The mixed brilliant faceting combined with the oval outline yields an efficient balance between weight retention and optical performance, preserving a large table plane while creating a lively crown and pavilion relationship that supports strong return of light in standard lighting conditions.

From a cutting and craftsmanship perspective this chrysoberyl demonstrates careful attention to facet geometry and symmetry, consistent with precision lapidary practice. The mixed brilliant style is executed here with a brilliant style crown of multifaceted kite and star facets over a large table, married to a pavilion that incorporates both shallow and deeper facets to optimize internal reflection for a refractive index in the chrysoberyl range. The result is minimized extinction along the long axis and well controlled light leakage at the girdle in typical mounting scenarios. Facet junctions are crisp and polish quality is excellent, producing clean facet windows and sharp facet contrast, which enhances scintillation. The oval proportions were chosen to balance the need for face up coverage and depth compensation, and the pavilion depth works with the chosen crown angles to favor return of white light and color retention rather than dispersive fire.

Optically chrysoberyl occupies a distinctive position among near colorless and green to yellow green gem species. The refractive index range for chrysoberyl is approximately 1.746 to 1.755, yielding a higher index than beryl varieties for example heliodor which typically run near 1.57 to 1.60, and higher than peridot which typically runs near 1.65 to 1.69. Birefringence in chrysoberyl is low but measurable, typically in the range 0.008 to 0.012, so facet edges remain crisp without the pronounced doubling seen in high birefringence materials. Hardness is a notable advantage for daily wear, with Chrysoberyl near 8.5 on the Mohs scale, and specific gravity in the neighborhood of 3.73 to 3.78, which contributes to a satisfying heft relative to similarly sized gems. Luster in chrysoberyl is commonly described as subadamantine to adamantine, which in practice manifests as bright, mirror like facet reflections and strong contrast between light and shadow areas. Dispersion or fire is modest in chrysoberyl when compared to highly dispersive stones, so the visual appeal relies more on facet brightness, crisp reflections, and color saturation than on spectral flashes.

When compared to other gemstones in its green and yellow green category, this yellowish green chrysoberyl demonstrates a unique blend of brilliance and color stability. Against peridot, chrysoberyl shows higher refractive power and a more distinctly adamantine luster, which translates to crisper highlights and greater contrast under point light sources, while peridot often shows a softer, oilier shine and tends to be more pleochroic when cut thin. Against beryl family stones such as heliodor and emerald, chrysoberyl delivers superior surface reflectance and edge brightness due to the higher refractive index, whereas beryl examples rely more on color depth and windowing management to achieve visual impact. Compared with green tourmaline, chrysoberyl tends to return light in a tighter, more mirror like fashion, since tourmaline often displays strong pleochroism and variable saturation that can cause color zoning and differential light return. When contrasted with demantoid garnet, chrysoberyl will show less dispersion and therefore less prismatic fire, however chrysoberyl compensates with a firmer, more durable surface and a clearer expression of intense body color without the play of spectral colors that dominates demantoid appeal. Compared with alexandrite, which is the color change variety of chrysoberyl, this yellowish green material lacks pronounced color change, but retains the dense optical mass and similar refractive response that give chrysoberyl species their characteristic brilliance under white light.

In summary this 7.91 carat oval yellowish green chrysoberyl from Ceylon Sri Lanka offers a technically refined optical performance ideal for clients who prioritize precision cutting, material integrity, and everyday durability. The mixed brilliant cut maximizes the return of light and cultivates lively scintillation while preserving a generous face up appearance, the intense color intensity provides strong saturation without the need for enhancement, and the very slightly included clarity at eye level ensures that the visual field is clean and the stone performs well in a variety of mounting styles. For buyers seeking the balance of adamantine luster, structural hardness, and an elegant green yellow hue, this gem presents a desirable option. The Natural Gemstone Company is pleased to offer this specimen, and we welcome technical inquiries regarding mounting recommendations, appraisal documentation, or imaging under specific lighting for comparison with other materials.