Stibiconite with pen for scale. From the mineral collection of Brigham Young University Department of Geology, Provo, Utah, Mineral Specimens 1032. Courtesy of the U.S. Geological Survey Denver Library Photographic Collection. (Photo by Andrew Silver.)

Formula: Sb3O6(OH) Orthorhombic


Stibiconite is a white to yellowish mineral that forms as a result of the alteration of other antimony-rich minerals, such as stibnite.

MARATHON COUNTY: Falster( 1987) reports stibiconite as white crusts on sulfosalts in quartz in vugs in the pegmatites of the Wausau Pluton, such as is exposed in the “rotten granite” quarries south of Rib Mountain.