Some properties of artificial orthorhombic anhydrite

Abstract

The properties were examined of a number of samples of soluble anhydrite and calcium sulphate hemihydrate in which substantial conversion to orthorhombic anhydrite had taken place. Large deviations from the properties of the mineral were found in the density and reactivity of orthorhombic anhydrite formed at low temperatures. The experimental results are discussed in relation to the nature, formation, and determination of orthorhombic anhydrite present in preparations of calcium sulphate hemihydrate and soluble anhydrite. Conclusions drawn from previous work on the reactivity of calcium sulphate hemihydrate are evaluated in the light of the present findings.