10.29 Ct. Ametrine from Ceylon (Sri Lanka)

From the warm, mineral rich soils of Ceylon this remarkable bi color ametrine began its story as a crystalline formation growing slowly within a pocket of quartz, capturing within its structure the subtle interplay of iron and natural irradiation that yields its twin personalities of golden citrine and royal amethyst. Our miners and sourcing partners who work with The Natural Gemstone Company view each crystal as a small chapter in a longer geological narrative, and this one was selected for its transparent clarity and the unusually clean boundary where the two colors meet. The stone arrived to the cutting studio with promise, and our cutters treated it with respect and restraint, allowing the natural zoning to dictate the final shape and facet plan. This provenance in Sri Lanka imparts a cultural resonance, and the gem carries a quiet elegance that speaks of tropical geology, traditional craftsmanship, and the careful selection process that defines The Natural Gemstone Company.

We present this gem as a transparent, emerald cut bi color ametrine weighing 10.29 carats, with dimensions of 15.59 by 10.71 by 7.91 millimeters, and with a clarity grade of eye clean when evaluated at eye level. The cutter chose an emerald cut to emphasize the stone body and the linear transition between purple and yellow, to showcase the medium intense color intensity, and to allow broad step facets to act like mirrors that reveal the internal color split with calm brilliance. The polish was executed to an excellent standard, producing smooth, even facets that return light with a soft, glossy sheen. An enhancement of heat treatment was applied, disclosed and stable, to balance and intensify the citrine tones while respecting the natural amethyst areas, resulting in a gem that is vibrant without being overstated. In hand and on the finger this stone offers the noble presence of a large, well cut gem, and the emerald cut gives it a refined architecture that flatters both classic and contemporary settings.

In comparative terms this ametrine reflects light and color in a manner characteristic of quartz based gems, with a refractive index near 1.55 and a modest dispersion that produces a clear, luminous appearance rather than the sharp, fiery scintillation found in higher refractive index gems. When you hold this ametrine next to a pure amethyst or a pure citrine you will notice the same glass like brilliance and even light return, but the intrigue here comes from the dual tones and the way the emerald cut frames the color boundary. Compared to tourmaline, which usually exhibits stronger pleochroism and a higher refractive index, this ametrine feels more serene and luminous, favoring broad flashes of color over pronounced flashes of sparkle. Compared to corundum gems such as sapphire, which have a higher refractive index near 1.76 and greater fire, the ametrine offers a gentler glow, a more contemplative brightness, and a subtler play of light that suits larger table facets. The step cut minimizes scintillation and maximizes color contrast, so the reflective quality is about clarity, color purity, and the way each broad facet becomes a canvas for the two colors to converse.

At The Natural Gemstone Company we see this stone as more than a commodity, it is a wearable story, a conversation starter, and a canvas for custom design. Its 10.29 carat weight and substantial footprint make it ideal for a statement ring, a centerpiece pendant, or a bespoke cuff that celebrates the bi color transition. Because the gem is eye clean and well polished, it will present beautifully in settings that allow light to enter freely, and the emerald cut will lend any piece an elegant, architectural silhouette. We disclose the heat treatment openly, and we recommend gentle care that avoids sudden temperature changes and harsh chemicals, as with all quartz family gems. If you would like design ideas, custom mounting options, or a private viewing, our team at The Natural Gemstone Company is ready to guide you through metal choices and setting styles that will complement the medium intense colors and the emerald cut. This ametrine is a rare opportunity to wear a gem that tells a geological story, and to own a piece that celebrates both nature and the skill of the cutter who revealed its two toned soul.