Celestite or strontium sulfate (SrSO4) is currently known as a common source of strontium. The name Celestite is derived from Celestial which means a very beautiful sky blue color. This mineral crystallizes in the orthorhombic system. Its outline color is white and it has a specific weight of 3.9 grams per cubic centimeter. Beautiful crystals, good polish and extraordinary color of celestite are its distinctive features. Most celestite samples show fluorescence under ultraviolet light.

The total production of celestite in the world in 2006 was 500,000 tons, of which Iran had a small share in this global production with the production of 7,500 tons. Spain, Germany and China can be identified as the most important consumption centers of this mineral

Meanwhile, after the exploration and exploitation of the studied mineral range and the addition of more than 5 million tons of reserves and the annual production of 100,000 tons, Iran’s position as one of the largest countries with economic reserves of celestite and one of the producers of Most of this mineral has been significantly upgraded.

The strontium mines in Semnan Province are mined in an open-pit and stepped manner to produce strontium ore and then strontium carbonate, in special factories used due to easy access, to Celestine stone in a special geological structure that exists in Semnan Province, mining with its main problem, i.e. tailings. There will not be large-scale extractions, that is why the work of strontium deposits and mines in the province has been greatly welcomed, and Semnan Province has become one of the poles of strontium production in the country.