(Guido di Castello) flourished 12th century, Italian ecclesiastic: pope 1143–44.
- Celestine III
(Giacinto Bobone) died 1198, Italian ecclesiastic: pope 1191–98.
- Celestine IV
(Godfrey Castiglione) died 1241, Italian ecclesiastic: pope 1241.
- Celestine V
Saint (Pietro di Murrone or Morone) 1215–96, Italian ascetic: pope 1294.
a white to pale-blue mineral, strontium sulfate, SrSO 4 , occurring in tabular crystals, the principal ore of strontium. noun a white, red, or blue mineral consisting of strontium sulphate in orthorhombic crystalline form: a source of strontium compounds. Formula: SrSO4