Prehnite
Ca2Al2Si3O10(OH)2

     Prehnite is another rare species at MSH.

PHYSICAL CHARACTERISTICS:

Color is usually white or tan.
Luster is vitreous to pearly.
Diaphaneity is translucent to transparent.
Crystal System is orthorhombic; P2cm.
Crystal Habits include compact radiating aggregates to 1cm, blocky
   crystals to 0.5mm
Cleavage {001} is good and {110} is poor.
Fracture is uneven.
Hardness is 6 - 6.5
Specific Gravity is approximately 2.95 g/cm3.
Streak is white.
Associated Minerals include calcite and grossular.
Distinguishing Features: Crystal habit.
Origin: Named in 1789 after Colonel Hendrick von Prehn (1733-1785),
   who discovered the mineral at the Cape of Good Hope, South Africa.

CLASSIFICATION:

Dana System
# 72.1.3.1

Strunz Classification
# VIII/G.07-30

REFERENCES:
MinRec 21:330 (1990), Dana 8:1522-1523 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
¤¤¤

PE
--

AP
--

MX
¤¤

SS
--

MC
--

HF
¤¤

BR
--

SX
--

FR
--

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