LUZONITE
Luzonite – Cu3AsS4 – is a rarer sulfide, occurring as a primary mineral in copper ores.
It is part of the Stannite Group and contains 48.4% Cu. As impurity, may contain Sb.
1. Characteristics
Crystal system: Tetragonal scalenohedral.
Color: Deep pinkish-brown
Habit: Massive, granular. Crystals very rare and small, equant (pseudo-octahedral) in habit.
Cleavage: {101} good, {100} distinct.
Tenacity: Brittle.
Twinning: On {112}.
Fracture: Irregular, conchoidal.
Mohs Hardness: 3.5
Parting: No.
Streak: Black
Lustre: Metallic
Diaphaneity: Opaque.
Density (g/cm³): 4.4 – 4.6
2. Geology and Deposits
Luzonite ocurr as primary mineral in copper ores, but is not a common sulfide.
3. Mineral Associations
It ocurrs with common gangue mineral like quartz and pyrite.
As a typical sulfide of copper ores, luzonite ocurrs with tennantite-tetrahedrite, enargite, chalcopyrite, colusite and covellite.
Also with rares sulfides as goldfieldite and nekrasovite.
4. Transmitted Light Microscopy
Does not apply, because luzonite is completley opaque.
5. Reflected Light Microscopy
Sample preparation: no information available.
PLANE POLARIZED LIGHT – PPL
Reflection color: no information available.
Pleochroism: Weak.
Reflectivity: ~25%
Bireflectance: No.
CROSSED POLARIZED LIGHT – XPL
Isotropy / Anisotropy: Strong anisotropy between greenish yellow and purplish.
Internal reflections: No.
May be confused with: No information available.
General Characteristics:
