82.19 Ct. Lemon Quartz

One transparent 82.19 carat oval lemon quartz is presented with precise dimensions of 34.70 x 25.07 x 17.48 mm, exhibiting an oval outline that maximizes face up area while retaining ideal depth for optical performance, the mixed brilliant cut combines a brilliant crown with a modified pavilion geometry to balance scintillation and light return, clarity is graded as eye clean when examined at eye level, color intensity is classified as intense lemon yellow throughout the stone, polish has been evaluated as excellent, there is no enhancement, origin is unknown, and this specimen is offered by The Natural Gemstone Company. Physically, quartz is trigonal and uniaxial positive, its refractive index ranges approximately from 1.544 to 1.553, birefringence is modest at about 0.009, dispersion is low in the order of 0.013 which limits spectral fire compared with higher dispersion gems, and the combination of these inherent optical constants with the cutting design is responsible for the gem s characteristic brilliance and controlled flash. The substantial dimensions and significant carat weight allow for a generous facet program without compromising pavilion angles, and the uniform intense color combined with an eye clean clarity grade permits maximized facet contrast and unhindered internal reflection.

The gem s internal structure and the cutter s chosen faceting schema are the decisive factors that produce a sparkle that is difficult to replicate in other materials, the trigonal lattice of quartz yields consistent optical behavior across the body of the stone, and because the material is uniaxial positive the optic axis orientation relative to the table and long axis of the oval was managed to prevent undesirable birefringent doubling and to concentrate light return into strong, organized flashes. The mixed brilliant style uses a dense crown facet pattern with kite, star, and upper girdle facets that break incident light into numerous small flashes, while the pavilion is arranged to direct those flashes back through the crown rather than allowing them to leak through the girdle, the result is a lively scintillation that reads as both large flashes at lower viewing angles and a delicate pinfire when the stone is moved. Oval proportions elongate the optical path length, enhancing color saturation and permitting multiple internal reflections along the long axis, the excellent polish minimizes surface scattering and maximizes specular reflection, and with the stone being eye clean, there are no significant inclusions to interrupt the internal light train, these combined factors create a balance between overall brilliance, localized scintillation, and color saturation that produces a perceptible sparkle unique to a well cut, large lemon quartz.

For buyers who appreciate comparative gemology and setting considerations, a brief note about White Opal is included as requested, white opal is a hydrated amorphous form of silica characterized by a light body tone and the potential for play of color resulting from the diffraction of light by silica spheres, its optical behavior is primarily structural interference rather than refractive index governed refraction, white opal s specific gravity is lower than quartz and it is more sensitive to heat and sudden changes in humidity, therefore when pairing a White Opal with a quartz such as this lemon specimen it is advisable to design a setting that protects the opal from direct heat sources while allowing the quartz to display its strong facet driven brilliance, for mounted presentations the oval lemon quartz benefits from a low profile bezel or a well engineered prong system that secures the girdle without obscuring the crown facets, crown and pavilion symmetry should be preserved during setting to maintain the engineered light paths that produce its signature sparkle, The Natural Gemstone Company can provide detailed facet maps and setting recommendations upon request, we advise independent gemological verification for buyers requiring certification, and we are available to discuss custom mounting options that respect the material properties of both quartz and white opal.