celsian
/ˈsɛlsɪən/Mineralogy
noun
A colourless, white, or pale yellow mineral of the monoclinic crystal system which is a barium-containing feldspar, BaAl2Si2O8, dimorphous with paracelsian and occurring mostly in association with manganese deposits.
Origin
Late 19th century; earliest use found in Mineralogy Magazine. From Swedish celsian from the name of Anders Celsius + -an.