Soil water likely monitoring: a gypsum block could be inserted into the soil, and its electrical resistance may be calculated to derive soil humidity.[48] Crystal Technique: Gypsum crystals belong to the monoclinic crystal system. This crystal framework has three unequal axes, with one angle in between axes being non-ninety levels. https://www.propanraya.com/id/produk/eco-gypsum-ee-4050