millisite
/ˈmɪlɪsʌɪt/Mineralogy
noun
A light grey or white hydrated basic phosphate of sodium, potassium, calcium, and aluminium, (Na,K)CaAl6(PO4)4(OH)9·3H2O, crystallizing in the tetragonal system and occurring as finely fibrous crusts and spherules.
Origin
1930s. From the name of F. T. Millis, of Lehi, Utah + -ite.