A white, pale green, or pale green crystalline mineral, basically KCa4Si8O20(F,OH)·8H2O.
any one of a number of types of a pale green or green mineral becoming a mixed fluoride and silicate of potassium and calcium.
A mineral concerning the zeolites, frequently occurring in square prisms or octahedrons with pearly luster from the cleavage area. It is a hydrous silicate of calcium and potassium.
A mineral allied into the zeolites, occurring in laminated masses or in tetragonal crystals, and achieving a powerful pearly luster on the surface of perfect cleavage, parallel to which it separates readily into thin laminæ.