White acicular goslarite crystals. From La Union, Sierra de Cartagena, Spain. Field of view is about 1.8 mm. (Photo courtesy Jesse Crawford; unauthorized reproduction is prohibited.)

Formula: ZnSO4.7H2O Orthorhombic


Goslarite is an alteration product of sphalerite and other zinc minerals. It is water soluble and dehydrates readily under surface conditions, hence, although it may frequently form, it is only rare found and preserved given Wisconsin’s climate. Goslarite has been reported from several of the zinc mines in the upper Mississippi Valley zinc lead district where it is intermixed with melanterite, copiapite, epsomite and gypsum (Heyl et al., 1959).

LAFAYETTE COUNTY: Goslarite occurs at the Helena-Roachdale Mine, in the center of section 7 T.1N. R.2E., near Shullsburg (Heyl et al., 1959).