Vesuvianite
Ca₁₀Mg₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)₇

     Vesuvianite is relatively common at MSH.

PHYSICAL CHARACTERISTICS:

Color varies from pale yellow to lemon-yellow, orange-yellow, brown,
   greenish brown.
Luster is vitreous to resinous.
Diaphaneity is transparent to translucent, opaque on larger crystals.
Crystal System is tetragonal; P4/nnc.
Crystal Habits include tabular crystals to 1.5cm and acicular crystals
   to 1.5cm that may form attractive spherical aggregates to 2.5 cm;
   occasionally as embedded crystals or irregular grains.
Cleavage {110} is indistinct, {010} and {000} are very indistinct.
Fracture is uneven to subconchoidal.
Hardness is 6 - 7.
Specific Gravity is approximately 3.4 g/cm³.
Streak is white.
Associated Minerals include aegirine, analcime, andradite, apophyllite
   series, biotite, calcite, fluorite, grossular, microcline, molybdenite,
   natrolite, pectolite, pyrite and sodalite.
Distinguishing Features: Crystal habit and forms.
Origin: Named in 1795 after its discovery locality, in ejected volcanic
   blocks at Mount Vesuvius, Campania, Italy.

CLASSIFICATION:

REFERENCES:
MinRec 21:344-345 (1990), Dana 8:1213-1215 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

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