CaAlSi10(OH)
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; cm
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/cm
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
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