Noun
Native strontium sulphate, a mineral so named from its occasional delicate blue color. It occurs crystallized, also in compact massive and fibrous forms.
Source: Webster's dictionaryAlthough celestite finds frequent usage in some mineralogical texts, the name has been discredited as a valid mineral name by this organization. Source: Internet
Of the two, celestite occurs much more frequently in deposits of sufficient size for mining. Source: Internet