0.57 ct HAUYNE – Sar-e-Sang – AFGHANISTAN – CERTIFIED

Greenish-Blue Haüyne (Sar-e-Sang, Afghanistan)

Certified on – 04/04/26 by GIL Lab Bangkok

Greenish-Blue Haüyne from the historic, high-altitude metamorphic marble horizons of Sar-e-Sang, Badakhshan, Afghanistan, represents one of the most intriguing and sought-after color transitions within the sodalite group. Bridging the gap between the classic deep cobalt-lapis hue and the ultra-rare yellow variant, this specialized greenish-blue material is a species I have always respected for its “electric-cyan” to “vivid-lagoon-teal” saturation and its status as a masterclass in “isometric” structural discipline. For the specialist, a fine Afghan Greenish-Blue Haüyne—whether presenting as an ultra-rare, loop-clean faceted collector gem or sharp, lustrous dodecahedral crystals anchored in snowy calcite—is a prized trophy of volatile-rich skarn metasomatism; it offers a bright vitreous to greasy surface luster and a luminous, deeply captivating presence that makes it an essential anchor for the systematic vault. As an artist, I find the breathtaking, sea-green to Caribbean-teal light transmission radiating from within its crystal bodies to be one of nature’s most sophisticated and visually arresting palettes.

The Heritage & Discovery

Historical Significance Greenish-blue haüyne is a vital index species for decoding the delicate sulfur-fugacity shifts, high-temperature metamorphism, and volatile-rich fluid movements that govern the legendary lapis lazuli deposits of the Hindu Kush. Historically, while European haüyne from volcanic ejecta (such as the Eifel region of Germany) is universally known for saturated royal blue, the deep metamorphic skarns of Badakhshan provide a completely unique geological setting. Mined continuously for thousands of years, these ancient Afghan marble units allow haüyne to co-crystallize with a complex array of feldspathoids, capturing subtle polysulfide and sulfur-radical variations that give rise to rare intermediate cyan, teal, and greenish-blue colorations.

Discovery The unearthing of gem-quality greenish-blue haüyne crystals within the rugged marble cliffs of Sar-e-Sang provided mineralogists with a fascinating study in chromophore dynamics. Scientifically, Haüyne contains open framework cages in its crystal structure that house sulfate (SO4 2-) anions alongside variable sodium and calcium. In standard royal-blue specimens, trisulfur radical anions (S3-) dominate the absorption spectrum; in greenish-blue Afghan material, a precise geochemical balance occurs where minor disulfur radicals (S2-) or localized polysulfide color centers mix with the blue-absorbing centers. This specific chromophore combination allows green and blue-green wavelengths to transmit cleanly, creating a distinct lagoon-teal to cyan body color. My own respect for this material grew from analyzing its diagnostic optical profile; specifically, observing its vivid neon-teal transmission under direct daylight reveals a fluid-like optical depth that is unmistakable to the trained eye.

Important Mines The undisputed international capital for this rare variety is the legendary Sar-e-Sang Mine, located in the Koksha Valley of the Kuran wa Munjan District, Badakhshan Province, Afghanistan. Operating in sheer, high-altitude alpine terrain, these ancient workings yield world-class specimens from contact metamorphic marble beds where silica-undersaturated pegmatites interacted with ancient evaporite-bearing limestones. For the vault, I prioritize specimens that exhibit sharp, unblemished crystal terminations, uniform greenish-blue or teal saturation without muddy gray overtones, strong internal translucency, and a pristine matrix anchor of white calcite, diopside, or phlogopite.

Mineralogical Profile

Description Greenish-Blue Haüyne is a complex sodium calcium aluminum silicate sulfate mineral belonging to the feldspathoid/sodalite group that crystallizes in the isometric system. It sits at a moderate 5.5 to 6 on the Mohs scale, meaning its highly lustrous crystal faces are tough but somewhat brittle, featuring distinct dodecahedral cleavage that requires careful archival handling to protect its crisp crystal edges, terminations, and polished gem facets from physical shock or abrasion. It is characterized by its bright vitreous to greasy surface luster and a vibrant, tropical color palette dominated by electric greenish-blue, lagoon-teal, cyan, and deep sea-foam green.

One of its most identifying traits is its isometric crystal habit, routinely forming modified dodecahedrons, rounded contact grains, or compact crystalline pods embedded within stark marble. It possesses a relatively low refractive index running from approximately 1.496 to 1.508, giving faceted stones and crystal edges a soft, liquid-like depth, paired with a light average specific gravity ranging between 2.40 and 2.50 that reflects its porous, cage-like framework. Because it forms exclusively in volatile-rich, silica-undersaturated metamorphic and skarn environments, it is commonly found in close association with Calcite, Diopside, Phlogopite, Sodalite, Afghanite, Lazurite, and Pyrite. When I select an example for documentation, I look for sharp crystal geometry, intense greenish-blue color saturation, and exceptional optical clarity, as these emphasize the sophisticated, fluid-driven chemistry of the mineral’s dramatic subterranean birth.

Chemical Formula Na3Ca(Si3Al3)O12(SO4) (with mixed S3- and S2- polysulfide chromophore centers)