1. Gypsum-based materials and lightweighting

1.1 Gypsum

Gypsum, also known as plaster stone or alabaster, is a sedimentary rock formed by chemical precipitation from the evaporation of calcium salts dissolved in salt lakes or seawater. Precipitation of part of the evaporites, made up of calcium, magnesium and potassium chlorides and sulfates, is common in nature and forms large areas where gypsum is mined or quarried.

This mineral consists mainly of calcium sulfate dihydrate (CaSO ₄ (H ₂ O) ₂ ) and occurs in nature as various crystalline phases, of which selenite (with hexagonal crystals) and alabaster (polycrystalline formations) are the most common