Gypsum

**History and Etymology of Gypsum**:
– The word ‘gypsum’ is derived from the Greek word γύψος (gypsos), meaning plaster.
– Quarries in Paris provided burnt gypsum known as plaster of Paris.
– Gypsum was known as ‘spærstān’ in Old English.
– Johann Friderich Mayer promoted gypsum’s use as a fertilizer in the 18th century.
– The Plaster War of 1820 was fueled by the demand for gypsum as a fertilizer.

**Physical Properties and Crystal Varieties**:
– Gypsum crystals are soft and can bend under hand pressure.
– Gypsum exhibits retrograde solubility and perfect cleavage along sheets.
– Varieties include selenite, alabaster, and desert roses.
– Selenite can form some of the largest crystals in nature, up to 12m long.

**Occurrence and Synthesis**:
– Gypsum is common in evaporite beds and is often found with halite and sulfur.
– Unique conditions in White Sands National Park have created white gypsum sand.
– Synthetic gypsum is produced as a waste product in industrial processes.
– Flue gas desulfurization gypsum can replace natural gypsum in various applications.

**Refinery Waste and Occupational Safety**:
– Phosphogypsum and titanium gypsum are byproducts of industrial processes.
– Legal exposure limits for gypsum are set by OSHA and NIOSH.
– Proper safety measures are crucial to prevent health risks associated with gypsum exposure.
– Impurities in refinery gypsum waste hinder its use in construction, leading to storage and leaching risks.

**Uses and Applications of Gypsum**:
– Gypsum is extensively used in construction, agriculture, modeling, sculpture, art, food, drink, medicine, cosmetics, and various industries.
– It serves as a fertilizer, soil conditioner, coagulant, water hardness regulator, dough conditioner, and mineral yeast food component.
– Gypsum is valued for its diverse properties and applications in different sectors.