5.12 Ct. Bi Color Ametrine from Brazil

This listing describes one beautiful transparent 5.12 carat, emerald cut, bi color ametrine, with exact dimensions of 12.07 x 8.46 x 6.48 mm, faceted to emphasize clarity and color zoning. The stone presents a striking division between rich golden yellow and saturated violet, with intense color intensity and a clarity grade of very very slightly included, evaluated at eye level. The table and step facets of the emerald cut provide a crisp outline and controlled light return, the polish is excellent, and the overall finish displays clean facet junctions and symmetrical proportions. Enhancement has been disclosed as heat treated, a common and stable practice used to optimize tone and uniformity, and the origin of this ametrine is Brazil, with provenance and treatment disclosed in full by The Natural Gemstone Company.

The geological narrative of this ametrine spans millions of years, beginning deep within the earth where silica rich fluids migrated through fractures in host rock during prolonged regional metamorphism and hydrothermal activity. Trace amounts of iron and intermittent exposure to natural radiation resulted in distinct color centers as the crystal grew, a process influenced by subtle variations in temperature, pressure, and chemical environment at different stages of growth. In a single crystal, localized differences in oxidation state and thermal history produced sectors with the purple hues characteristic of amethyst, and adjacent sectors with the warm golden tones of citrine. Over immense periods of time, continued crystallization, cyclic heating events, and tectonic movements allowed these zones to stabilize and to be preserved within the quartz lattice. Later uplift, erosion, and secondary hydrothermal pulses concentrated gem quality material in vein systems and alluvial deposits in regions of Brazil known for their quartz varieties.

When this particular rough crystal was selected for cutting, the cutter established an orientation that preserved the natural bi color zoning while maximizing weight retention and optical performance. The emerald cut was chosen deliberately to showcase the linear separation of color, and to produce broad, flat facets that create a ribbon like presentation of the two tones when faced toward the viewer. The faceting sequence balanced step facets on the pavilion and crown to enhance internal color contrast while minimizing windowing and ensuring even light dispersion. At 5.12 carats and with dimensions of 12.07 x 8.46 x 6.48 mm, the gem presents an ideal scale for center stone settings where a clear demarcation between violet and yellow creates visual interest without overwhelming a mounting. The very very slightly included clarity, as observed at eye level, supports a bright, transparent appearance, and the excellent polish allows clean surface reflections that emphasize the quality of the cut.

As supplied by The Natural Gemstone Company, this ametrine is offered with full disclosure of origin and treatment, and with guidance for long term care. Heat treatment has been applied to enhance color balance where appropriate, and the effect is stable under normal wear conditions. Recommended care includes periodic cleaning with warm soapy water and a soft brush, avoiding harsh chemicals and extended exposure to extreme heat. While quartz varieties are generally durable, standard precautions are advised to protect against hard knocks and abrasive contact. This specimen is well suited for custom jewelry applications that benefit from a controlled, architectural cut, and for collectors who seek examples that illustrate the dual nature of ametrine formation. The combination of transparent clarity, intense color saturation, precise emerald cutting, and documented Brazilian origin provides a technically informative and naturally evocative example of a gem that records a lengthy geological history within a single, elegant form.