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Gismondine
Ca2Al4Si4O16 · 9H2O

     There are only a few confirmed specimens of gismondine from Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color is usually colorless to very pale pink.
Luster is vitreous.
Diaphaneity is transparent to translucent.
Crystal System is monoclinic; P21/c.
Crystal Habits include pseudo-octahedral to 1mm.
Cleavage {101} is distinct.
Fracture is conchoidal.
Hardness is 4.5
Specific Gravity is approximately 2.25 g/cm3.
Streak is white.
Associated Minerals include analcime.
Distinguishing Features: Crystal habit.
Origin: Named in 1817 after Carlo Giuseppe Gismondi (1762-1824),
   who first examined the mineral.

CLASSIFICATION:

Dana System
# 77.1.3.1

Strunz Classification
# VIII/J.25-20

REFERENCES:
MinRec 21:312 (1990), Dana 8:1661-1662 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
--

SS
--

MC
--

HF
--

BR
¤¤

SX
--

FR
--

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