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Posnjakite
Cu4(SO4)(OH)6 · 2H2O

     Posnjakite occurs rarely at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color is usually greenish-blue.
Luster is vitreous.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic; Pc.
Crystal Habits include efflorescences.
Cleavage is perfect.
Fracture is uneven.
Hardness is 2 - 3.
Specific Gravity is approximately 3.3 g/cm3.
Streak is bluish.
Associated Minerals include UK #55.
Distinguishing Features: Crystal habit, color and streak.
Origin: Named in 1967 after Eugene Waldemar Posnjak (1888-1949),
   American geochemist.

CLASSIFICATION:

Dana System
# 31.4.1.1

Strunz Classification
# VI/D.03-10

REFERENCES:
Dana 8:643 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
--

SS
--

MC
--

HF
--

BR
--

SX
¤¤

FR
--

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