ELBAITE IN QUARTZ

ABOUT THE SPECIMEN Complete, well-terminated crystals of blue-green cap elbaite tourmaline hosted within a well-sized reverse scepter quartz crystal. White albite is also present in parts of the specimen. The main quartz crystal has strong translucency in areas that allow one to see the embedding of the tourmaline straight through it. It's rehealed in many places, with complex growth all around, and the reverse scepter termination is pristine. Alluring and unique combination piece!   VIDEO   MORE INFO Stak Nala sits in the northeastern Nanga Parbat–Haramosh Massif at elevations above 3,000 meters, where Himalayan leucogranitic magmas emplaced prior to 5 Ma crystallized as flat-lying miarolitic pegmatite sills cutting granulitic gneiss at roughly 1.5–2 kbar. Laurs et al. (1998) demonstrated that the pegmatites show symmetrical internal zonation from a schorl-bearing wall zone inward to a K-feldspar and quartz core punctuated by miarolitic pockets - the cavities where elbaite, quartz, cleavelandite, and lepidolite crystallized in late-stage fluid-dominated conditions. Color zoning in elbaite progresses from iron- and manganese-bearing green in the interior through colorless manganese-bearing zones outward to a trace trivalent manganese pink cap at the termination - a chemical sequence faithfully recorded as visible color bands. Doubly terminated crystals exhibiting hemimorphism, where the two ends display different crystal forms, are a Stak Nala signature rarely matched elsewhere. Quartz on matrix tends toward short, glassy prisms nestled in platy cleavelandite alongside the tourmaline. The locality was first worked in the mid-1980s, with the finest material recovered in the earliest years of extraction; a subsequent pocket in late 2005 produced a secondary pulse of quality specimens. Fine tricolored doubly-terminated crystals on undamaged matrix have become progressively harder to source as early-find material continues to be absorbed into permanent collections.