1.4 cm. (Photo by W. Cordua.)
Formula: (Ca,Na,vacancy)19(Al,Mg,Fe)13(vacancy,B,Al,Fe)5(Si2O7)4(SiO4)10(OH,F,O)10 Tetragonal
Description:
Vesuvianite most commonly forms in metamorphosed calc-silicate rocks.
OCONTO COUNTY: Vesuvianite reportedly occurs with garnet, scapolite, clinopyroxene, hornblende and plagioclase in the Waupee Formation in the Mountain area. Here it is found as a contact metamorphic mineral where the Waupee formation is adjacent to the Hagar granite (Lahr, 1972).