Gypsum

Historical and Cultural Aspects: The word ‘gypsum’ is derived from the Greek word ‘gypsos,’ meaning plaster. Quarries in the Montmartre district of Paris provided burnt gypsum known as plaster of Paris. Johann Friderich Mayer promoted gypsum’s use as a fertilizer in the 18th century. The Plaster War of 1820 was fueled by American farmers’ demand for gypsum. Gypsum has historical significance as a construction material and in agriculture. Gypsum has been utilized in German agriculture since ancient times. Physical Properties and Crystal Varieties: Gypsum crystals are soft and can bend under hand pressure. Gypsum is moderately watersoluble and exhibits retrograde solubility. Gypsum’s structure consists of layers of calcium and sulfate ions bonded by water molecules. Gypsum occurs as flattened crystals, selenite, and granular forms like alabaster. Alabaster, a finegrained variety of gypsum, is used for ornamental work. Gypsum can be transparent, opaque, or fibrous in different forms. Occurrence and Synthesis: Gypsum is commonly found in thick evaporite beds with sedimentary rocks. Gypsum can form in caves, such as the Naica Mine in Mexico, with large crystals. Synthetic gypsum is a byproduct of industrial processes like flue gas desulfurization. Gypsum scaling in brackish water desalination affects membrane life. White Sands National Park in New Mexico has extensive gypsum sand deposits. Gypsum byproduct from desulfurization is used in water treatment and construction. Industrial Applications and Occupational Safety: Gypsum is widely used in construction, Portland cement, and agriculture. OSHA sets legal exposure limits for gypsum in the workplace. NIOSH provides recommended exposure limits for gypsum. Compliance with exposure limits is crucial in U.S. workplaces. Gypsum is approved as a food additive. Proper handling and disposal of gypsum are essential for safety. Scientific Studies and Agricultural Benefits: Studies on gypsum include solubility, crystal growth kinetics, and environmental impacts. Gypsum plays a role in managing sodic soils and improving soil water potential. The chemistry of sodic soil reclamation with gypsum and lime has been studied. The Soil Science Society of America recognizes gypsum as an agricultural product. Gypsum application in agriculture aids in improving soil structure and crop yield.