Luzonite

Cu3 AsS4
c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Tetragonal. Point Group: 42m. Crystals rare, to 2 mm; commonlycoarse-grained, fine-grained, massive, intimately intergrown with enargite. Twinning: Common
on {112}, also polysynthetic in polished section.
Physical Properties:
Cleavage: Good on {101}, distinct on {100}. Hardness = 3.5
VHN = n.d. D(meas.) = 4.38 D(calc.) = 4.53
Optical Properties: Opaque. Color: Deep pinkish brown, similar to bornite, althoughdarker; in polished section, pale brownish pink. Streak: Black. Luster: Metallic, dull.
Pleochroism: Weak. Anisotropism: Strong, in greenish yellow and purplish.
R1 –R2 : (400) 27.2–28.7, (420) 25.6–27.6, (440) 24.1–25.6, (460) 23.6–24.7, (480) 23.4–24.5, (500)
23.7–25.2, (520) 24.1–26.4, (540) 24.3–27.1, (560) 24.9–27.7, (580) 25.6–28.5, (600) 26.5–29.1, (620)
27.3–29.6, (640) 28.1–29.9, (660) 28.6–30.1, (680) 28.7–30.0, (700) 28.7–30.0
Cell Data:

Space Group: I42m. a = 5.332(5)c = 10.57(1)Z=2

X-ray Powder Pattern: Mankayan, Philippines.
3.046 (10), 1.855 (9), 1.592 (7), 1.578 (6), 1.204 (6), 1.078 (6), 1.321 (5)Chemistry:Cu
AsSbS

(1)
48.32
17.35
1.48
32.85

(2)
48.4
17.4
1.0
32.2

(3)
48.42
19.02
32.56

Total [100.00]
99.0
100.00(1) Mankayan, Philippines; recalculated to 100.00% after deduction of 0.97% insol. and 0.56%pyrite. (2) Huaron, Peru; by electron microprobe. (3) Cu3 AsS4 .
Polymorphism & Series:
Mineral Group:

Dimorphous with enargite; forms a series with famatinite.

Stannite group.

Occurrence: In hydrothermal Cu–As–Sb-rich vein and disseminated deposits, formed at low to
medium temperatures.
Association: Enargite, tetrahedrite–tennantite, colusite, stannoidite, pyrite, chalcopyrite,
covellite, sphalerite, bismuthinite, silver sulfosalts, silver, gold, marcasite, alunite, barite, quartz.
Distribution: From the Lepanto mine, Mankayan, Luzon, Philippines [TL], as an ore mineral.
In the Chinkuashi mine, Keelung, Taiwan. In Japan, at the Teine, Morino, and Date mines,
Hokkaido; the Kasuga and Akeshi mines, Kagoshima Prefecture; and other localities. Fromthe Sierra Famatina, La Rioja Province, Argentina. In the Julcani district, at Cerro de Pasco,and at Huaron, Peru. In the USA, in Nevada, at Goldfield, Esmeralda Co., from the Golden
Chariot mine, Jamestown district, Nye Co., and in the Burrus vein, Pyramid district, Washoe Co.;
from Butte, Silver Bow Co., Montana; and at Summitville, Rio Grande Co., Colorado. At theChelopech deposit, Sofia, Bulgaria. From Calabona, Sardinia, Italy. At the Kadzaharan deposit,Armenia. From Pı̂rı̂ul lui Avram, Romania. In the Lahóca Hill mine, Recsk, Mátra Mountains,Hungary. Numerous additional localities are now known.
Name:For Luzon Island in the Philippines.

References: (1) Gaines, R.V. (1957) Luzonite, famatinite and some related minerals.
Amer. Mineral., 42, 766–779. (2) Marumo, F. and W. Nowacki (1967) A refinement of thecrystal structure of luzonite, Cu3 AsS4 . Zeits. Krist., 124, 1–8. (3) Pósfai, M. and M. Sundberg(1998) Stacking disorder and polytypism in enargite and luzonite. Amer. Mineral., 83, 365–372.
(4) Pósfai, M. and P.R. Busek (1998) Relationships between microstructure and composition in
enargite and luzonite. Amer. Mineral., 83, 373–382. (5) Criddle, A.J. and C.J. Stanley, Eds.
(1993) Quantitative data file for ore minerals, 3rd ed. Chapman & Hall, London, 334.
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