Blue celestite, also called celestine, is a strontium sulfate mineral known for its delicate sky-blue, pale gray-blue, or nearly colorless crystals. It commonly forms in sedimentary rocks, especially limestone, dolostone, and evaporite deposits, where mineral-rich groundwater allows crystals to grow in cavities and geodes. Blue celestite is found in locations including Madagascar, Egypt, Mexico, the United States, Poland, and parts of Europe. Its crystals are often transparent to translucent and may appear as tabular or prismatic formations with a glassy to pearly luster.

In metaphysical traditions, blue celestite is associated with peace, calmness, gentle communication, and spiritual awareness. It is often believed to encourage relaxation, support meditation, and promote a sense of emotional clarity and harmony. Some practitioners connect it with the throat and higher spiritual energy centers, viewing it as a stone for expressing thoughts compassionately and strengthening intuition. These properties are based on spiritual beliefs and have not been scientifically established.