Apophyllite

phyllosilicate

zeolite

Apophyllite refers to a three minerals:
Fluorapophyllite-(K) KCa4Si8O20F.8H2O
Fluorapophyllite-(Na) NaCa4Si8O20F.8H2O and
Hydroxyapophyllite-(K) KCa4Si8O20(OH,F).8H2O
They are all phyllosilicates (sheet silicates)
Specific gravity: 2.3 to 2.4
Hardness: 4½ to 5
Streak: White
Colour: Colourless, white, yellow, green, brown, pink
Solubility: Moderately soluble in hydrochloric acid
Environments:

Basaltic cavities

Apophyllite occurs as a secondary mineral lining cavities in basalt and related rocks, associated with zeolites, calcite, datolite and pectolite.

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