Sanmartinite Locality: Mulatos, Sahuaripa Municipality, Sonora, Mexico Dimensions: 15 mm x 13 mm x 13 mm Description: A rare member of the wolframite group; acquired in 2002 from a rare-mineral dealer. Collection and photo Erik Vercammen. — Photo: Erik Vercammen · CC BY 3.0
Sanmartinite
A rare zinc tungstate — the zinc member of the wolframite group.
Intro adapted from Wikipedia (CC BY-SA).
Sanmartinite is an IMA-recognized mineral species in the tungstate class, with the chemical formula Zn(WO₄).
It crystallizes in the monoclinic crystal system (space group P-1). It is a member of the Wolframite structural group.
Key properties: specific gravity 6.7; Resinous luster.
IMA symbol Sma, grandfathered status — known before the IMA’s founding, named in 1948.
A rare alteration product of scheelite in a quartz vein between granite and granite pegmatite intruding Precambrian crystalline schists.
It is found associated with Willemite, scheelite, tourmaline, quartz.
The name refers to its occurrence near San Martı́n, Argentina.