Acanthite
Ag₂S

     Acanthite is a rare mineral at Mont Saint-Hilaire.

PHYSICAL CHARACTERISTICS:

Color is usually black.
Luster is metallic.
Diaphaneity is opaque.
Crystal System is monoclinic; P2₁/n.
Crystal Habits a flat acicular crystals to 2mm.
Cleavage: {001} is indistinct.
Fracture is subconchoidal.
Hardness is 2 - 2.5
Specific Gravity is approximately 7.3 g/cm³.
Streak is black.
Associated Minerals include (??).
Distinguishing Features: Crystal habit, color and luster.
Origin: Named in 1855 from the Greek akantha, a thorn, alluding
   to the shape of the crystals.

CLASSIFICATION:

REFERENCES:
Dana 8:42 (1997)

DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:

Legend