Wilcoxite

Formula: MgAl(SO4)2F.18H2O

Origin of name: for William Wilcox, American prospector, who discovered this mining district in 1879. He was killed by Apache Indians in 1880.

 

Crystal system: Triclinic

Crystal class: 1

Twinning:

Unit cell: a = 14.9, b = 6.65, c = 6.77, α = 117.433°, β = 100.583°, γ = 89.167°

 

Colour: Colourless, pale blue, pale green, will become milky white on exposure to air

Diaphaneity: Transparent to translucent

Luster: Greasy

Habit: Crystals prismatic, encrustations, efflorescences, spongy masses, may be stalactitic

Hardness: 2

Specific gravity: 1.58

Cleavage: none

Tenacity: Conchoidal fracture

Streak: White

 

Synonyms/varieties:

 

Comments:  Water soluble, will dissolve in its own water

 

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