Luzonite - Encyclopedia
Class : Sulfides and sulfosalts
Subclass : Sulfides
Crystal system : Tetragonal
Chemistry : Cu3AsS4
Rarity : Rare to uncommon
Luzonite is a rare copper-arsenic sulfide found in low- and medium-temperature hydrothermal mineralization. It is the dimorph of enargite, rarer than the latter. It is particularly common in copper porphyry and gold-bearing epithermal deposits, where it accompanies numerous sulfides and sulfosalts (bornite, digenite, pyrite, enargite, tetrahedrite, etc...). Its name derives from its discovery location : the Lepanto mine on the island of Luzon (Philippines). Luzonite is generally massive, exceptionally in corroded crystals with curved faces of 2 mm maximum, constantly showing polysynthetic twins. It is dark reddish brown, dark purplish brown to steel gray in color. It is an accessory copper ore.
Main photo : Luzonite from Chinkuashih mine, Taiwan © Y. Okazaki
Luzonite in the World
Twinning
A twin is known on {112}.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 3.55
Density : 4.4 to 4.6
Fracture : Irregular to conchoidal
Streak : Black
TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None
Solubility : Acids
Magnetism : NoneRadioactivity : None