Nagyágite(Te, Au)Pb(Pb, Sb)S2c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Monoclinic, pseudotetragonal. Point Group: 2/m. Thin tabular crystals, to1 cm, platy on {010}, commonly bent, with striations on (001) k [100] and [010]; also granularmassive. Twinning: Crossed twin lamellae exhibited on (001) sections.
Physical Properties:
Cleavage: Perfect on {010}, excellent on {101}. Tenacity: Flexible,slightly malleable. Hardness = 1.5 VHN = 60–94 (100 g load). D(meas.) = 7.35–7.49
D(calc.) = 7.29
Optical Properties: Opaque. Color: Blackish lead-gray; pale gray in polished section.
Streak: Blackish lead-gray. Luster: Metallic, bright on fresh cleavage. Pleochroism: Weak in airand oil. Anisotropism: Weak but distinct.
R1 –R2 : (400) 46.4–48.4, (420) 45,4–47.4, (440) 44.5–46.7, (460) 43.6–45.9, (480) 42.9–45.1, (500)42,1–44.2, (520) 31.3–43.3, (540) 40.5–42.4, (560) 39.8–41.6, (580) 39.2–40.9, (600) 38.7–40.3, (620)
38.3–39.8, (640) 37.8–39.2, (660) 37.2–38.6, (680) 36.6–37.8, (700) 36.0–37.2
Cell Data: Space Group: P 21 /m (synthetic).
β = 95.42(3)◦ Z = 2

a = 4.220(1)b = 4.176(1)c = 15.119(3)X-ray Powder Pattern: Săcărı̂mb, Romania.
3.023 (100), 2.829 (80), 2.081 (50), 2.431 (40), 1.511 (40), 1.823 (30), 1.710 (30)
(1)
(2)
(3)
Chemistry:(1)
(2)
(3)
Sb
7.39
7.68
7.8
Pb 56.81
56.76
58.8
Te
17.72
16.97
15.1
Au
7.51
7.47
9.0
S
10.76
10.83
10.1
Ag
0.10
0.17
Fe0.410.02
Total 100.60
99.85
101.0Cu0.02(1) Săcărı̂mb, Romania; corresponding to (Te0.81 Au0.22 )Σ=1.03 Pb1.00 (Pb0.60 Sb0.36
Fe0.04 )Σ=1.00 S2.00 . (2) Do.; by electron microprobe, average of 61 analyses on one specimen;
corresponding to (Te0.78 Au0.22 )Σ=1.00 Pb1.00 (Pb0.62 Sb0.37 )Σ=0.99 S2.00 . (3) Cripple Creek,Colorado, USA; by electron microprobe, corresponding to (Te0.71 Au0.28 Ag0.01 )Σ=1.00
Pb1.00 (Pb0.71 Sb0.39 )Σ=0.99 S2.00 .
Occurrence:

In Au–Te-bearing epithermal hydrothermal veins.

Association: Altaite, petzite, stutzite, sylvanite, tellurantimony, coloradoite, krennerite,arsenic, gold, proustite, rhodochrosite, arsenopyrite, sphalerite, tetrahedrite (Săcărı̂mb, Romania);
calaverite, gold, tellurobismuthite, altaite, galena, pyrite (Bohuliby mine, Czech Republic).
Distribution: In Romania, from Săcărı̂mb (Nagyág) [TL] and Baia-de-Arieş (Offenbánya).
In the Bohuliby mine, Jı́lové gold deposit, Czech Republic. From the Chelopech deposit, Sofia,Bulgaria. At Schellgaden, Austria. From Manka, Kazakhstan. At Zod, Armenia. In the Glen
Rosa mine, Selukwe, Zimbabwe. In the USA, from Gold Hill, Boulder Co., and Cripple Creek,Teller Co., Colorado; in the Dorleska mine, Coffee Creek district, Trinity Co., California; from theMayflower mine, Tobacco Root Mountains, Madison Co., Montana; and at the Foote mine, KingsMountain, Cleveland Co., North Carolina. In Canada, in the Huronian mine, Moss Township,Ontario; and from the Olive Mabel claim, Gainer Creek, British Columbia. At Farallon Negro,Catamarca Province, Argentina. In the Kalgoorlie district, at Oroya, and in the Golden Miledeposit, Western Australia. From the Sylvia mine, Tararu Creek, New Zealand. In the Rendaiji
mine, Shizuoka Prefecture, Japan. From the Tarua gold field, Vitu Levu, Fiji Islands.
Name:

For the Săcărı̂mb (Nagyág), Romania locality.

References: (1) Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy,(7th edition), v. I, 168–169. (2) Stumpfel, E.F. (1970) New electron probe and optical dataon gold tellurides. Amer. Mineral., 55, 808–814. (3) Stanley, C.J., A.C. Roberts, and D.C.
Harris (1994) New data for nagyagite. Mineral. Mag., 58, 479–482. (4) Effenberger, H., W. H.
Paar, D. Topa, F.J. Culetto, and G. Giester (1999) Towards the crystal structure of nagyagite,[Pb(Pb, Sb)S2 ][(Au, Te)]. Amer. Mineral., 669–676. (5) Criddle, A.J. and C.J. Stanley, Eds. (1993)
Quantitative data file for ore minerals, 3rd ed. Chapman & Hall, London, 388.
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