Petarasite (TL)

NaZrSi₁₈(Cl,OH) · 2H

Petarasite, a member of the lovozerite group, was described at Mont Saint-Hilaire in 1980. It is relatively uncommon at MSH, there were some excellent crystals found in the Fall of 1997.

PHYSICAL CHARACTERISTICS:

Color is varies from light to dark greenish-yellow, yellowish-brown,
orange to orange-yellow, brown and rasberry red.
Luster is vitreous to greasy.
Diaphaneity is transparent, translucent to opaque.
Crystal System is monoclinic; 2/
Crystal Habits include superb prismatic crystals to 5cm; equant,
blocky, tabular crystals and irregular grains to 10mm; rasberry red
crystals are micro (less than 1mm).
Cleavage {110} is perfect, {010} is very good and {001} is distinct.
Fracture is subconchoidal.
Hardness is 5 – 5.5
Specific Gravity is approximately 2.88 g/cm
Streak is white.
Associated Minerals include aegirine, albite, analcime, ancylite,
arfvedsonite, astrophyllite, calcite, cancrinite, catapleiite, eudialyte,
fluorite, galena, låvenite, microcline, natrolite, nepheline, pyrochlore,
pyrrhotite, rhodochrosite, rinkite (mosandrite) and sodalite.
Distinguishing Features: Crystal habit.
Origin: Named in 1980 after Peter Tarassoff (b. 1934), Canadian
metallurgical engineer.

CLASSIFICATION:

Dana System
# 61.1.2b.3

Strunz Classification
# VIII/E.16-70

REFERENCES:
CanMin 18:497-502 (1980), CanMin 18:503-509 (1980),
CanMin 19:411-413 (1981), MinRec 21:329-330 (1990),
Dana 8:1249 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH
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