Rickardite

Cu3−x Te2 (x = 0 to 0.36)
c 2001-2005 Mineral Data Publishing, version 1

Crystal Data: Orthorhombic, pseudotetragonal. Point Group: 2/m 2/m 2/mfine grained, somewhat porous; may be botryoidal.
Physical Properties:
Tenacity: Brittle. Hardness = 3.5
D(meas.) = 7.54 D(calc.) = 7.467

Massive, very

VHN = 72–85 (50 g load).

Optical Properties: Opaque. Color: Purple-red on fresh surface, tarnishes rapidly.
Luster: Metallic. Pleochroism: Strong; carmine to violet-gray. Anisotropism: Strong;
exceptional, in fiery orange colors.
R1 –R2 : (400) 28.3–37.2, (420) 26.1–35.5, (440) 23.5–33.2, (460) 20.8–30.5, (480) 17.8–27.5, (500)15.1–24.8, (520) 12.8–22.3, (540) 11.5–20.3, (560) 11.8–18.9, (580) 14.5–18.2, (600) 19.6–18.4, (620)26.0–19.4, (640) 32.7–21.0, (660) 38.6–23.3, (680) 43.9–26.0, (700) 48.1–28.6
Cell Data:
Z=2Space Group: P mmn (synthetic).

a = 3.9727(4)b = 4.0020(5)c = 6.1066(3)X-ray Powder Pattern: Good Hope Mine, Colorado, USA.
2.07 (100), 3.36 (60), 2.55 (40), 1.988 (40), 1.158 (30), 2.82 (20), 1.706 (20)
Chemistry:CuTe(1)
40.74
59.21

(2)
40.0
60.9

Total 99.95
100.9(1) Good Hope mine, Colorado, USA; corresponds to Cu2.76 Te2.00 . (2) Do.; by electron
microprobe, corresponds to Cu2.64 Te2.00 .
Occurrence: A late-stage mineral of low-temperature hydrothermal origin in some Te-bearing
mineral deposits.
Association: Vulcanite, tellurium, cameronite, petzite, sylvanite, berthierite, pyrite,
arsenopyrite, bornite.
Distribution: In the USA, in Colorado, at the Good Hope mine, Vulcan, Gunnison Co. [TL];
also at the Empress Josephine mine, Bonanza district, Saguache Co., at Buckeye Gulch, LakeCo., and elsewhere; in Arizona, from the Junction and Campbell mines, Bisbee, and the Little
Joe shaft, Tombstone, Cochise Co. In the Horne mine, Noranda, Quebec, Canada. From the San
Miguel prospect, 10 km southwest of Moctezuma, Sonora, Mexico. At the Lomo Hierro silver
deposit, western Cuba. From the El Indio mine, El Indio-Tambo district, east of La Serena,Coquimbo, Chile. In Japan, from the Teine mine, Hokkaido, and the Kawazu mine, Shizuoka
Prefecture. From Kalgoorlie, Western Australia. In South Africa, at Ookiep, Namaqualand. Fromthe Byn’govsk Au–Te deposit, Ural Mountains, and the Koshmansaisk deposits, Chatkal Ridge, inthe basin of the Arbulak River, Russia. At Zlata Bana, Slanske vrchy Mountains, Czech Republic.
Other occurrences are known.
Name: In honor of Thomas Arthur Rickard (1864–1953), mining engineer and Editor of theEngineering and Mining Journal, New York and London.
Type Material:National Museum of Natural History, Washington, D.C., USA, 114590.

References: (1) Palache, C., H. Berman, and C. Frondel (1944) Dana’s system of mineralogy,(7th edition), v. I, 198–199. (2) Mizota, T., K. Koto, and N. Morimoto (1973) Crystallography
and composition of synthetic rickardite. Mineral. J. (Japan), 7, 252–261. (3) Schutte, W.J. andJ.L de Boer (1993) Determination of the incommensurately modulated structure of Cu3−x Te2 .
Acta Cryst., 49, 398–403. (4) Ramdohr, P. (1969) The ore minerals and their intergrowths,(3rd edition), 416–417. (5) Criddle, A.J. and C.J. Stanley, Eds. (1993) Quantitative data file forore minerals, 3rd ed. Chapman & Hall, London, 480.
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