Celestine It is a mineral consisting of strontium sulfate. The mineral is named for its occasional delicate blue color. <PERSON> is the principal source of the element strontium, commonly used in fireworks and in various metal alloys. Crystals And Gemstones, Stones And Crystals, Gem Stones, Healing Crystals, Healing Stones, Gemstone List, Cool Rocks, Rocks And Gems, Rocks And Minerals