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Tangdanite, a new mineral species from the Yunnan Province, China and the discreditation of "clinotyrolite"

Ma Zhesheng, Li Guowu, N. V. Chukanov, G. Poirier and Shi Nicheng
Tangdanite, a new mineral species from the Yunnan Province, China and the discreditation of "clinotyrolite"
Mineralogical Magazine (June 2014) 78 (3): 559-569

Abstract

Tangdanite, ideally Ca (sub 2) Cu (sub 9) (AsO (sub 4) ) (sub 4) (SO (sub 4) ) (sub 0.5) (OH) (sub 9) .9H (sub 2) O and monoclinic, is a new mineral species (IMA No. 2011-096) occurring in the Tangdan and Nanniping mines, southeast Dongchuan copper mining district, Dongchuan County, Kunming City Prefecture, Yunnan Province, P. R. China (26 degrees 11'N 103 degrees 51'E). The mineral is found in the oxidized zone (gossan) of an As-bearing Cu sulfide deposit and is clearly of supergene origin. Associated minerals are chalcopyrite, bornite, chalcocite, covellite, tennantite, enargite, cuprite, malachite, azurite, copper and brochantite. Crystals form radiating or foliated aggregates of flaky crystals up to 3 mm, flattened parallel to (100) and elongated along [001]. It is emerald green with a light green streak, translucent and has a pearly to silky lustre. It is sectile having perfect cleavage on {100} although neither parting nor fracture was observed. No fluorescence in long- or short-wave ultraviolet radiation was observed. The hardness is VHN (sub 50) 42.0-43.6, mean 42.8 kg mm (super -2) (2-2 1/2 on the Mohs scale). The density measured by pycnometry is 3.22 g cm (super -3) (Ma et al., 1980). The calculated density from the empirical chemical formula is 3.32 g cm (super -3) . The compatability index gives 1 - (K (sub p) /K (sub c) ) = -0.041 (good). The empirical formula (based on 36 O a.p.f.u) of tangdanite is Ca (sub 2.05) Cu (sub 9.08) (As (sub 1.03) O (sub 4) ) (sub 4) (S (sub 0.63) O (sub 4) ) (sub 0.5) (OH) (sub 9) . 9H (sub 2.04) O. The simplified formula is Ca (sub 2) Cu (sub 9) (AsO (sub 4) ) (sub 4) (SO (sub 4) ) (sub 0.5) (OH) (sub 9) .9H (sub 2) O. The strongest five reflections in the X-ray powder-diffraction pattern [d in Aa (I) (hkl)] are: 4.782(100) (31 1 1), 4.333(71) (6 0 2), 5.263(54) (21 0 2), 3.949(47) (8 0 2) and 2.976(46) (151 1 1). The unit-cell parameters are a = 54.490(9), b = 5.5685(9), c = 10.4690(17) Aa, beta = 96.294(3) degrees , V = 3157.4(9) Aa (super 3) , Z = 4. Its structure was solved and refined in space group C2/c, with R = 0.110.


ISSN: 0026-461X
EISSN: 1471-8022
Coden: MNLMBB
Serial Title: Mineralogical Magazine
Serial Volume: 78
Serial Issue: 3
Title: Tangdanite, a new mineral species from the Yunnan Province, China and the discreditation of "clinotyrolite"
Affiliation: China University of Geosciences, Crystal Structure Laboratory, Beijing, China
Pages: 559-569
Published: 201406
Text Language: English
Publisher: Mineralogical Society, London, United Kingdom
References: 8
Accession Number: 2014-096923
Categories: Mineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 7 tables
N25°04'00" - N25°04'00", E102°40'60" - E102°40'60"
Secondary Affiliation: Russian Academy of Sciences, Institute of Problems of Chemical Physics, RUS, Russian FederationCanadian Museum of Nature, CAN, Canada
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, Copyright, Mineralogical Society of Great Britain and Ireland. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201449
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