NaFe³⁺Si₂O₆

Aegirine, a member of the pyroxene group, is one of the most abundant and conspicuous crystallized minerals occurring at Mont Saint-Hilaire. It is a major constituent in the pegmatites and occurs in varying degrees of abundance in most of the other mineral associations.

The crystals range in size from tiny, acicular, millimeter-size crystals often formed in radiating aggregates to superb, large, prismatic crystals up to 30cm in length. The crystals are typically well terminated.

PHYSICAL CHARACTERISTICS:

Color varies from pale to dark green (most common), yellow, brown,
and red for the acicular habits. The larger crystals are invariably black.
Luster is vitreous.
Diaphaneity is transparent to opaque in the larger crystals.
Crystal System is monoclinic; C2/c.
Crystal Habits the tetragonal dipyramid, equant and the tabular
habit with dominant pinacoid.
Cleavage: {110} distinct and {010} imperfect.
Fracture is conchoidal.
Hardness is 5 – 6.
Specific Gravity is approximately 3.3 g/cm³.
Streak is white.
Associated Minerals include almost all minerals.
Distinguishing Features: larger crystals exhibit large well terminated
crystals, while acicular habit presents pale colours.
Origin: Named in 1835 for Aegir, the Scandinavian god of the sea.

CLASSIFICATION:

REFERENCES:
MinRec 21:294 (1990), Dana 8:1305-1306 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

MSH          PE          AP          MX          SS           MC          HF           BR          SX          FR
¤¤¤           ¤¤          ¤¤            ¤¤          ¤¤            ¤¤          ¤¤             ¤¤          ¤¤           ¤¤

Legend