Calcium sulphate, represented by the chemical symbol CaSO4, is an exceptionally versatile mineral that finds application in a wide range of industrial, agricultural, and everyday settings. Exactly what is calcium sulfate? Calcium sulphate finds application in diverse sectors such as construction materials and food additives, owing to its remarkable attributes and advantages. This article will analyze the composition, properties, functions, and applications of calcium sulfate, shedding light on its importance across numerous disciplines.

Composition And Structure: 

Calcium sulfate is found in various forms, with gypsum (calcium sulfate dehydrate, CaSO4·2H2O) and anhydrite (calcium sulfate anhydrous, CaSO4) being the most prevalent. Soft sulfate minerals, including gypsum, naturally occur both as minerals and as components of sedimentary rock formations. In contrast, anhydrite is the anhydrous state of calcium sulfate; its crystalline structure is devoid of any water molecules. 

The crystal structure of calcium sulfate is distinguished by the lattice network arrangement of sulfate ions (SO42-) encircling calcium ions (Ca2+). Each calcium ion is bonded to two water molecules in gypsum, whereas these water molecules are absent in anhydrite, which produces a denser crystal structure. 


Calcium sulfate exhibits several fundamental properties that contribute to its extensive spectrum of applications: 

  • Solubility: Anhydrite is virtually insoluble in water, whereas gypsum is only moderately soluble. Gypsum is ideally suited for a diverse array of applications necessitating controlled dissolution on account of its solubility properties.
  • Hardness: Gypsum has a Mohs hardness of 2, which indicates that it is comparatively malleable and, therefore, simple to carve and shape. In contrast, anhydrite possesses a significantly greater Mohs hardness ranging from 3 to 3.5. 
  • Thermal Stability: Due to its thermal stability, calcium sulphate finds application in construction materials, fireproofing, and industrial operations, all while remaining stable at high temperatures. 
  • Hygroscopicity: Gypsum is capable of absorbing moisture from the air due to its hygroscopic properties. This attribute renders it practical for regulating relative humidity in specific applications. 

Utilisation And Implementation: 

Calcium sulfate’s multifunctionality enables its application in an extensive array of sectors and industries. 

  • Plaster of Paris: Gypsum is frequently employed in the production of plaster of Paris, an adaptable substance that finds applications in the fields of architecture, the arts, and medicine. The water-soluble plaster of Paris hardens rapidly, rendering it optimal for casting and molding applications. 
  • Drywall: Gypsum boards, alternatively referred to as gypsum or plasterboard, have extensive applications in the building industry as modules for interior walls and ceilings. A uniform surface finish, fire resistance, and sound insulation are all features of the gypsum interior. 
  • Soil Amendment in Agriculture: Gypsum is utilized as a calcium and sulphur fertilizer in a soil amendment to enhance water infiltration, promote soil structure improvement, and alleviate soil salinity. 
  • Animal Feed: Calcium sulfate is incorporated into animal feed as a calcium supplement with the dual purpose of promoting bone health and enhancing the quality of eggshells in poultry. 
  • Desiccation: A desiccant or dehydrating agent, anhydrous calcium sulfate is utilized to absorb moisture from liquids and gases used in industry. 
  • Food and Beverage: Food Additive: Regulatory authorities have certified calcium sulphate as a food additive (E516). It functions in various food products, including tofu, cheese, and baked goods, serving as a firming agent, thickener, and stabiliser. 
  • Brewing: Gypsum is frequently incorporated into fermentation water in order to modify the pH level and calcium ion concentration, thereby enhancing the beer’s flavor, clarity, and stability. 


Calcium sulphate, in its multifaceted nature, is indispensable in a multitude of sectors and implementations owing to its exceptional characteristics and adaptability. Calcium sulphate contributes to the fields of construction materials, agriculture, industrial processes, and food additives, all of which enhance sustainability, quality of life, and technological progress. This underscores the enduring significance of calcium sulfate in the contemporary world, as its importance is likely to increase in numerous disciplines as novel uses and applications for this mineral are discovered.