Canfieldite

Ag8 SnS6c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Orthorhombic, pseudocubic. Point Group: mm2. Crystals, to 1 cm, withcombinations of pseudo-octahedron and dodecahedron; also botryoidal with drusy surface;as small inclusions. Twinning: Commonly on {111}, as pseudospinel law twins, or repeatedinterpenetration twins of pseudododecahedra.
Physical Properties: Fracture: Conchoidal to uneven. Tenacity: Brittle. Hardness = 2.5
VHN = 90.7–171 (25 g load). D(meas.) = 6.2–6.3 D(calc.) = 6.311
Optical Properties: Opaque. Color: Steel-gray with reddish tinge, tarnishes black with blue
to purple tint; pale gray with violet tint in reflected light. Streak: Gray-black, somewhat shining.
Luster: Metallic.
R: (400) 33.0, (420) 30.8, (440) 28.9, (460) 28.0, (480) 27.2, (500) 26.5, (520) 25.9, (540) 25.5,(560) 25.2, (580) 25.1, (600) 24.9, (620) 24.9, (640) 24.8, (660) 24.8, (680) 24.8, (700) 24.9
Cell Data: Space Group: P na21 or P nam (synthetic).
c = 10.699(1) Z = 4

a = 15.298(2)b = 7.548(1)X-ray Powder Pattern: Synthetic.
3.114 (100), 3.085 (90), 1.8960 (90), 2.727 (70), 1.9129 (70), 3.252 (55), 3.232 (55)Chemistry:
AgFeSn

(1)
74.10
0.21
6.94

(2)
65.12

(3)
73.49

10.57

10.14

GeTeS

(1)
1.82
16.22

(2)

(3)

8.69
13.95

16.37

Total 99.29
98.33
100.00(1) Aullagas, Bolivia. (2) Revelstoke, Canada; by electron microprobe. (3) Ag8 SnS6 .
Polymorphism & Series:
Occurrence:

Forms a series with argyrodite; stable below 172 ◦ C.

In polymetallic veins, formed very late in the paragenetic sequence.

Association: Argyrodite, pyrargyrite, stephanite, acanthite, polybasite, freibergite, stannite,stannoidite, cassiterite, arsenopyrite, jordanite, marcasite, pyrrhotite, sphalerite, galena.
Distribution: In Bolivia, exceptional crystals from the Gallofa vein, Aullagas, near
Colquechaca, and at the Guadaloupe mine, Chocaya, Potosı́. From the Pirquitas deposit,Riconada Department, Jujuy Province, Argentina. In Canada, from about 33 km northeast ofRevelstoke, British Columbia. At the Campbell mine, Bisbee, Cochise Co., Arizona, and theLeadville district, Lake Co., Colorado, USA. In the Himmelsfürst mine, Erbisdorf, near Freiberg,Saxony, Germany. From Rejská, near Kutná Hora, and Přı́bram, Czech Republic. In the Ikuno
and Omidani mines, Hyogo Prefecture, and the Ashio mine, Tochigi Prefecture, Japan. At Shuiji,Jianyang Co., Fujian Province, China. From the Karamken Au–Ag deposit, Okhotsk district, andat the Belukhinsk tungsten deposit, eastern Transbaikalia, Russia. Other minor occurrences areknown.
Name: Honoring Frederick Alexander Canfield (1849–1926), American mining engineer andmineral collector of Dover, New Jersey, USA.
References: (1) Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy,(7th edition), v. I, 356–358. (2) Harris, D.C. and D.R. Owens (1971) A tellurium-bearing
canfieldite, from Revelstoke, B.C. Can. Mineral., 10, 895–898. (3) Wang, N. (1978) New
data for Ag8 SnS6 (canfieldite) and Ag8 GeS6 (argyrodite). Neues Jahrb. Mineral., Monatsh.,
269–272. (4) Soeda, A., M. Watanabe, K. Hoshino, and K. Nakashima (1984) Mineralogy oftellurium-bearing canfieldite from the Tsumo mine, SW Japan and its implications for ore
genesis. Neues Jahrb. Mineral., Abh., 150, 11–23. (5) Sugaki, A., A. Kitakaze, and H. Kitazawa(1985) Synthesized tin and tin-sulfide minerals; Synthetic sulfide minerals (XIII). Sci. Rep.,
Tohoku Univ., Ser. 3, 16, 199–211 (in English). (6) Criddle, A.J. and C.J. Stanley, Eds. (1993)
Quantitative data file for ore minerals, 3rd ed. Chapman & Hall, London, 71.
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