Thermochemical energy storage and conversion is yet considered as key technology enhancing the efficiency of energy production and utilization from renewables. Recently, several search algorithms and screening approaches for new materials for thermochemical energy storage and conversion have been published. Since respective reaction systems have to match numerous requirements, the demand for suitable materials in the low, middle and high temperature range is quite significant. However, recent works on reversible de- and rehydrations for application in the middle temperature range from 100 degrees C-400 degrees C are predominantly restricted to simple, binary compounds containing water of crystallization. Within the scope of the present work, a new search methodology based on a mineral classification system also including ternary or higher compounds is firstly subjected and experimentally validated. The experimental elaboration started from a small number of 29 compounds, from which already two suitable reaction systems are identified. For one of these reaction systems, orthorhombic calcium dizinc-bisphosphate dihydrate to calcium dizinc-bisphosphate monohydrate, the cycling stability is firstly proven on a mineral sample.