SMITHSONITE

ABOUT THE SPECIMEN

Botryoidal growth of rich, lemon-yellow smithsonite from a now exhausted locale. The appealing coloration was formerly thought to be caused by the presence of elemental cadmium, though samples have shown that it’s more likely due to inclusions of cadmium sulfides like hawleyite or greenockite. Yellow smithsonite has been found at a few localities worldwide, though I can only think of one or two others that had this rich yellow hue to them. Color aside, my favorite thing about this piece is the smooth rolling luster that goes all across. Front face is all in fantastic shape, there is peripheral damage on the sides, and the specimen is sawed flat on the back.

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Weinan sits within the Lanping-Simao basin of southeastern Yunnan, a region hosting major Pb-Zn carbonate replacement deposits; smithsonite formed secondarily in the oxidized zone above sphalerite ore as descending meteoric waters dissolved zinc and scavenged cadmium from the surrounding carbonate host. A 2023 gemological study of Yunnan smithsonite confirmed that cadmium substituting for zinc in the carbonate structure is the primary driver of intense yellow coloration - with microscopic greenockite inclusions acting as an additional yellow chromophore in some specimens, an interaction analogous to "turkey fat" smithsonite from other localities. The original find at Weinan occurred around 2003–2005 but was held as a hoard by the original collector until material began trickling into Western dealer networks around 2014–2015; a distinct late-2019 find produced a different expression - canary-yellow cadmian smithsonite partially replacing scalenohedral white calcite, interpreted as partial pseudomorphs - alongside white early-stage smithsonite cores later coated by a second generation of cadmian material, documenting multiple precipitation pulses. The locality appears to have been essentially inaccessible to systematic follow-up, and no significant production has been documented since 2019.