Inner part of a 1,7 cm fragment of the concretion-like sample with 2 types of mineral segregations. The green botryoidal one constits mainly of and oldhamite and fluorite with coexisting cuspidine, periclase and thaumasite (fluorite and cuspidine are more abundant in the outer part of the sample). The white zones are built up mainly with portlandite, periclase, spurrite and probably vaterite. The concretion appears to be formed by a few-step alteration (high temperature and hot gases activity, hydrolysis of the by-products) of the carbonate rock fragments, on an already recultivated, no more burning coal-dump.
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