Celsian is an uncommon feldspar , barium aluminosilicate, Ba 8. The mineral occurs in contact metamorphic rocks with significant barium is monoclinic , and it is white, yellow, or transparent in appearance. In pure form, it is transparent. Synthetic barium aluminosilicate is used as a ceramic in dental fillings and other applications.
The mineral is named after Anders Celsius (1701–1744).