Formula: NaCa4[Al9Si27O72].nH2O Monoclinic Description: Stilbite is a member of the zeolite family. It often forms vein and amygdule fillings in basaltic igneous rocks. ASHLAND COUNTY: Brownish plates of stilbite about 1 cm. in diameter are found in …
Ashland County
Zoisite
Formula: (Th,U)SiO4 Tetragonal Description: Thorite is a rare mineral found in pegmatites and hydrothermal deposits. Zoisite is formed in rocks subjected to low to medium grade metamorphism. If often results from the deterioration of plagioclase. It is …