Thumbnails
Thalcusite crystal – 3mm
© Gilles Haineault
TlCuFeS
Thalcusite occurs very rarely at Mont Saint-Hilaire.
PHYSICAL CHARACTERISTICS:
Color is usually dark gray to black.
Luster is metallic.
Diaphaneity is opaque.
Crystal System is tetragonal; 4/mmm
Crystal Habits include small and thin bladed crystals to 1mm.
Cleavage not apparent.
Fracture is (??).
Hardness is 2.5
Specific Gravity is approximately 6.6 g/cm
Streak is black.
Associated Minerals include aegirine, eudialyte, lovozerite, sodalite,
ussingite, villiaumite and vuonnemite.
Distinguishing Features: Crystal habit.
Origin: Named in 1976 for its composition: thallium, copper and
sulfur, (Thal + Cu + S + ite).
CLASSIFICATION:
Dana System
# 2.5.5.1
Strunz Classification
# II/F.04-30
REFERENCES:
MinRec 21:342 (1990), Dana 8:54 (1997)
DISTRIBUTION AND RARITY AT MONT SAINT-HILAIRE:
MSH
¤¤¤