Faustite

Faustite is a massive, bright green, zinc-rich member of the Turquoise group that is mined near near Neynschabour, Iran. It is the same structure as Turquoise but the copper element has been replaced by zinc.
General Information
Chemical Formula
(Zn,Cu)Al
 
6
(PO
 
4
)
 
4
(OH)
 
8
· 4H
 
2
O
Michael O’Donoghue, Gems, Sixth Edition (2006)
Photos of natural/un-cut material from mindat.org
Physical Properties of Faustite
Mohs Hardness4.5
Michael O’Donoghue, Gems, Sixth Edition (2006) About 4.5
Specific Gravity2.9
Michael O’Donoghue, Gems, Sixth Edition (2006) Near 2.9
TenacityBrittle
Anthony et al, Handbook of mineralogy (2001)
FractureConchoidal
Anthony et al, Handbook of mineralogy (2001) Small conchoidal to smooth
Optical Properties of Faustite
Refractive Index1.612
Michael O’Donoghue, Gems, Sixth Edition (2006) About 1.612
Optical CharacterBiaxial/+
Anthony et al, Handbook of mineralogy (2001)
BirefringenceMedium
Anthony et al, Handbook of mineralogy (2001)
Colour
Colour (General)Apple-green and yellow-green, light bluish green
Michael O’Donoghue, Gems, Sixth Edition (2006)
TransparencyTranslucent,Opaque
Anthony et al, Handbook of mineralogy (2001) Opaque, translucent on thin edges
LustreWaxy,Dull (Earthy)
Anthony et al, Handbook of mineralogy (2001)
Crystallography of Faustite
Crystal SystemTriclinic
Michael O’Donoghue, Gems, Sixth Edition (2006)
HabitMasses or nodules
Michael O’Donoghue, Gems, Sixth Edition (2006)
Geological Environment
Where found:Occurs as masses or nodules in argillized shales associated with copper mineralization.
Michael O’Donoghue, Gems, Sixth Edition (2006)
Further Information
Mineral information:Faustite information at mindat.org
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