The Crystal Cave

Apophyllite

KCa₄[(F,OH)|(Si₄O₁₀)₂] . 8H₂O

Silicates (phyllosilicates).
Apperance: Builds tabular crystals of cubic or octahedral apperance, sometimes even dipyramidal or platy crystals. Colors are colorless or white, even light shades of pink, yellow and green.
Hardness: 4,5-5
SG: 2,3-2,4
Transparent or translucent with pearly luster on basal faces.
Crystal system: Teragonal.
Environment: A hydrothermal mineral. Builds in basaltic and tufacious rocks cavities and are associated with calcite, prehnite, stilbit, scolecite and analcime.