13.86 Ct. Citrine from Brazil

This offering from The Natural Gemstone Company is a remarkable 13.86 carat natural citrine, cut as a cushion shape with dimensions of 15.03 by 13.81 by 11.22 millimeters, originating from Brazil, transparent throughout, and evaluated as eye clean at normal viewing distance. The stone exhibits an intense yellow color intensity, uniformly distributed across the pavilion and crown, with no evidence of colour zoning or artificial treatment, enhancement, or irradiation. The absence of enhancement preserves the natural chromophore profile and ensures the colour seen in white light is native to the crystal structure, a critical detail for connoisseurs who prioritize provenance and untreated material. The excellent polish and careful lapidary work present crisp facet junctions and high surface lustre, allowing the stone to project its warm hue with clarity and stability under both daylight and incandescent illumination.

Technically, the cutter employed a mixed brilliant style adapted to the cushion outline, combining a faceted brilliant crown with a pavilion configuration optimized to the refractive properties of quartz. The table and crown facets are proportioned to balance strong scintillation with broad flash, while the pavilion facets are arranged to promote internal reflection pathways that maximize light return. With a depth of 11.22 millimeters relative to an average girdle diameter of 14.42 millimeters the pavilion depth calculates to approximately 77.8 percent, a proportion that the cutter intentionally selected to increase internal mirror planes and to produce layered flashes rather than a single flat return. The cushion outline features slightly rounded corners and symmetrically radiating facet arrays, producing a checkerboardlike crown effect that contributes to the crisp, multifocal sparkle characteristic of high quality mixed cuts. The excellent polish minimizes microabrasions and surface diffusion, preserving the intended optical performance across viewing angles.

From an optical physics perspective, the sparkle generated by this citrine is a function of material refractive index, facet geometry, clarity, and colour saturation working in concert. Citrine, a variety of quartz, has a refractive index in the range of approximately 1.544 to 1.553 and a birefringence near 0.009, characteristics that produce strong internal reflection without high dispersion. Unlike stones with high dispersion where spectral fire dominates, this citrine achieves its unmatched sparkle through intense facet contrast and well engineered light pathways. The mixed brilliant arrangement creates multiple small mirror facets that break incident light into rapid, high contrast flashes, a phenomenon described as scintillation, while the eye clean clarity permits uninterrupted transmission and reflection of light across the pavilion and crown. The intense, warm yellow chroma contributes to perceived brilliance by absorbing blue wavelengths and enhancing the perception of brightness in the yellow to amber bands, producing vivid nearfield flashes that read as warmth and fire to the viewer. The absence of visible inclusions eliminates scattering centers that would otherwise diffuse light, so the gem returns concentrated flashes rather than clouded, low contrast glows. When rotated under a point light source, the stone presents a lively pattern of pinfire and broad flashes that is both dynamic and consistent, a direct result of precise facet alignment and the inherent optical parameters of natural quartz.

For practical use and setting considerations, the combination of 13.86 carat weight and generous cushion dimensions offers versatility for high end ring projects or bespoke pendants where the stone’s depth and facet architecture can be shown to advantage. A medium to tall profile prong setting with an open gallery will allow maximum light ingress to the pavilion, preserving the designed internal reflection paths, while a well executed bezel that leaves the crown exposed can provide everyday security without compromising optical performance. Warm yellow or rose gold settings will harmonize with the intense yellow body colour and enhance perceived saturation, while white metal settings provide a contemporary contrast that emphasizes brilliance and facet pattern. Given the Mohs hardness of quartz at 7, the stone is suitable for regular wear with reasonable care, and routine cleaning with mild soap and warm water and a soft brush will maintain the high polish and facet crispness. As with all natural gems offered by The Natural Gemstone Company, detailed imagery, viewing under balanced lighting, and provenance documentation can be provided on request, and our lapidary and design specialists are available to advise on mounting strategies that preserve the engineered light return that gives this Brazilian citrine its unmatched sparkle.