Tacharanite is a calcium aluminium silicate hydrate (C-A-S-H) mineral of general chemical formula Ca12Al2Si18O33(OH)36 with some resemblance to the calcium silicate hydrate (C-S-H) mineral tobermorite. It is often found in mineral assemblage with zeolites and other hydrated calcium silicates.
Globular, white tacharanite (diameter 2.5 mm) from Palagonia, Italy
Spherical, cream-coloured tacharanite on white Na-phillipsite (a mineral series of the zeolite group) from Palagonia, northern Iblean plateau, Sicily, Italy (field of view 1 cm).
Tobermorite is a calcium silicate hydrate mineral with chemical formula:
Ca5Si6O16(OH)2·4H2O or
Ca5Si6(O,OH)18·5H2O.
Crystalline mass of tobermorite