Sulfates: Celestite

Composition: SrSO₄; barium may substitute for strontium

Crystal system: Orthorhombic; variety of habits including tabular crystals and fibrous forms

6.5.1
cleavable celestite
OH USA

Properties:

• Vitreous lustre
• Variable color; colorless, white, pale blue, reddish or greenish
• White streak
• Knife scratches very easily; fingernail does not scratch (Mohs Hardness 3-3.5)
• Above average density
• Three cleavages of variable quality
• Cleaves rather than fractures unless finegrained
• Not ferromagnetic
• Does not react with hydrochloric acid (HCl)

Occurrence:

Celestite is the most common strontium mineral. It occurs with other sulfates in bedded deposits, in cavities and veins in limestones and also in some hydrothermal ore deposits.

6.5.2 cleavable celestite OH USA	6.5.3 celestite crystal OH USA

Celestite is the most important source of strontium which is mainly used in the manufacture of specialist glass.