39.86 Ct. Tourmaline from Tanzania

This specimen from The Natural Gemstone Company is a substantial and technically refined green tourmaline weighing 39.86 carats, with precise measurements of 24.95 by 17.01 by 13.32 millimeters. It is faceted in a classical emerald cut, employing elongated, stepped crown and pavilion facets that produce linear light return and a broad, flat table that emphasizes the stone body color. The gem is transparent with a clarity grade of very slightly included, evaluated at eye level, and the excellent polish is immediately apparent in the crisp facet junctions and mirror like facet surfaces. Color intensity is classified as dark, with a saturated green that shows subtle bluish nuances under certain angles. This piece has received no enhancement, and its provenance is Tanzania, a locality noted for producing deeply saturated and durable tourmalines. From an optical standpoint the material is consistent with tourmaline family parameters, with a refractive index approximately 1.624 to 1.644 and birefringence in the order of 0.014 to 0.020, and the stone displays pleochroic tendencies that shift between deep forest green and slightly bluish green when rotated with respect to the light source.

The emerald cut was chosen to maximize the perceived depth and color concentration of the rough, and the stepped faceting produces characteristic broad flashes rather than scintillating brilliance. This faceting style makes any internal zoning or color banding more apparent, and this particular piece does exhibit linear color zoning that runs approximately parallel to the table, producing alternating bands of deeper and slightly lighter green when viewed from different angles. Those working the setting should take the zoning into account, since face up appearance can be brightened by orienting the banding to favor the table view, or alternatively a profile oriented mount can be used to feature the banding as a design element. The very slightly included clarity at eye level means that inclusions do not interfere with the transparency or structural integrity, and the excellent polish ensures clean light paths. Tourmaline rates around 7 to 7.5 on the Mohs scale, so standard jewellery practices apply, and corner protection is advisable for an emerald cut. Four corner prongs placed at the beveled corners or a low profile bezel will protect the stone from impact, while an open back or gallery in the mounting will allow additional light to enter the pavilion, reducing the visual density of the dark tone if a brighter face up look is desired.

From a design and colour theory perspective the dark, saturated green of this Tanzanian tourmaline is remarkably versatile when set in metal, and specific combinations will accentuate different undertones in the wearer. For cool undertones and fair complexions, white metals such as platinum or rhodium plated white gold will create a crisp contrast that emphasizes the bluish green pleochroic component, producing a cooler, more jewel like appearance. For warm undertones, and for those seeking to bring out the yellow green warmth in the stone, traditional yellow gold or warm rose gold will add reflected warmth and lift the midtones, making the green read as more vibrant and lively. Olive complexions are uniquely well suited to both yellow and white metals, with yellow gold enhancing the warmer facets of the tourmaline and white metal accents reinforcing the deeper green, creating a balanced effect. Deeper skin tones provide a dramatic background that allows the gem to read as intensely saturated, and in these cases both high polished white metal settings and rich yellow gold can be chosen to either isolate the cool green or to create a warm contrast. Practical setting choices will also influence perceived colour, with open backed settings and prong mounts favoring increased light transmission and a brighter face up aspect, and full bezels or closed backs producing a darker, more intense presentation. The emerald cut long axis is flattering in finger rings when set parallel to the finger, elongating the hand, while a transverse orientation produces a bold cocktail statement. If you would like precise mounting recommendations or a CAD mock up for this specific 39.86 carat Tanzanian tourmaline, contact The Natural Gemstone Company and our gem specialists will provide detailed guidance tailored to your design and skin tone preferences.