39.67 Ct. Blue Aquamarine from Brazil

This transparent cushion shape aquamarine weighs 39.67 carats, and measures 23.17 x 20.99 x 13.75 millimeters, presenting a commanding face up presence coupled with substantial depth. The cutting style is faceted, executed as a mixed brilliant cut, and the stone displays a medium color intensity with a cool sea blue that is characteristic of fine Brazilian material. Clarity is graded as very slightly included when evaluated at eye level, and the specimen exhibits excellent polish across all facets. This aquamarine has been heat treated, a stable and widely accepted enhancement for beryl that shifts greenish undertones toward a purer blue, and the provenance is Brazil, a region known for producing clean rough with attractive blue tones. The Natural Gemstone Company presents this gem as an example of precision cutting married to thoughtful material selection, offering a rare balance of size, transparency, and calibrated color saturation.

The mixed brilliant cut of this cushion was chosen deliberately to optimize the way light is captured, reflected, and returned to the observer, taking into account the optical constants of beryl. With a measured depth of 13.75 millimeters against an average face dimension of approximately 22.08 millimeters, the depth proportion is approximately 62.3 percent, a proportion that supports strong internal light return without creating excessive windowing or dark extinction. The cutter combined a relatively broad table and a well proportioned crown with a modified pavilion geometry, creating a network of smaller crown facets to generate lively scintillation, while using graduated pavilion facets to stabilize large volume flashes of color. The refractive index of aquamarine, around 1.577 to 1.583, sets the critical angle for total internal reflection, and the facet angles here are calibrated to maintain frequent total internal reflections across a range of viewing angles, producing both brilliance and controlled dispersion. The mixed brilliant plan also works to distribute color evenly across the face up area, converting internal blue saturation into crisp, directional flashes of light, and the excellent polish minimizes surface scattering so that light interacts predominantly with internal facet planes.

Craftsmanship considerations extended beyond pure optical performance to include orientation relative to internal features and cleavage planes inherent to the beryl crystal structure. The cutter oriented the pavilion to minimize the visual impact of very slight inclusions, positioning them along facet junctions where return light and scintillation help to mask contrast, and the result is a gemstone that reads cleaner at typical viewing distances. Heat treatment was applied under controlled conditions to enhance blue saturation without compromising the structural integrity of the crystal, a standard practice for aquamarine that yields durable and permanent improvement in hue. For setting, open prong or low bezel designs will maximize light entry and emphasize the stone s mixed brilliant dynamics, while deeper settings can be used when the goal is to accentuate the deep blue flashes created by the pavilion geometry. The Natural Gemstone Company stands behind the reported attributes, offering detailed imagery and measurements upon request, and can advise on mounting styles that will best showcase the exceptional optical behavior of this 39.67 carat Brazilian aquamarine, ensuring the final piece highlights the thoughtful fusion of material quality and precision cutting.