Zeophyllite Locality: Starý hill (Alter Berg), Radejčín (Radzein), Řehlovice, Ústí nad Labem (Aussig), Ústí Region, Bohemia (Böhmen; Boehmen), Czech Republic Spheres and radial aggregates of Zeophyllite from the TL: Alter Berg at Radzein near Velký Brezno, Ústi Region, Bohemia, Czech Republic. Classic specimen from 1905. Field of view 6 cm. Specimen and photo Leon Hupperichs — Photo: Leon Hupperichs · CC BY-SA 3.0
Zeophyllite
Zeophyllite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₁₃Si₁₀O₂₈(OH)₂F₈·6H₂O.
It crystallizes in the hexagonal crystal system (space group R-3).
Key properties: Mohs hardness 3; specific gravity 2.75–2.76; Pearly luster; optically uniaxial.
IMA symbol Zp, grandfathered status — known before the IMA’s founding, named in 1902.
Found in cavities, as a secondary mineral from hydrothermal alteration of basalt (Litom·e·rice, Czech Republic).
It is found associated with Zeolites, apophyllite.
Its name comes from the Greek to boil and a leaf, in allusion to its habit.