Delhayelite

Formula:  (Na,K)10Ca5Al6Si32O80(Cl2,F2,SO4)3 . 18H2O

Origin of name:  Named for Fernard Delhaye (1880-1946), Belgian geologist, a pioneer in the geological exploration of the northern Kivu region of Zaire.

 

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell: a = 13.06, b = 24.65, c = 7.04

 

Colour:  Colourless, light gray-green

Diaphaneity: Transparent

Luster:

Habit:  Crystals platy

Hardness: 4.5

Specific gravity:  2.60

Cleavage:  1; {010} distinct

Tenacity:

Streak: White

 

Synonyms/varieties:

 

Comments:

 

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