Celestite Geode Large Celestine Mineral SpecimenPurchase A Blue Celestite Half Geode This is a stunning Celestite geode specimen with significant, dreamy, sky blue crystal points throughout. The geode's exterior is raw and unpolished. Celestine, or celestite, is a mineral consisting of strontium sulfate. The mineral is named for its occasional delicate blue color. Celestine and the carbonate mineral Strontianite are the principal sources of strontium, commonly used in fireworks and various metal