DRIEKOPITE, IDEALLY PtBi, A NEW MINERAL SPECIES FROM THE DRIEKOP PLATINUM PIPE, REPUBLIC OF SOUTH AFRICA

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F23%3A10168913" target="_blank" >RIV/00025798:_____/23:10168913 - isvavai.cz</a>

Result on the web

<a href="https://doi.org/10.3749/2300005" target="_blank" >https://doi.org/10.3749/2300005</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3749/2300005" target="_blank" >10.3749/2300005</a>

Result language

angličtina

Original language name

DRIEKOPITE, IDEALLY PtBi, A NEW MINERAL SPECIES FROM THE DRIEKOP PLATINUM PIPE, REPUBLIC OF SOUTH AFRICA

Original language description

The new mineral driekopite, ideally PtBi, was found in a concentrate from the Driekop mine, one of three zoned Pt pipes (mined from 1925 to 1930) that crosscut the layered mafic and ultramafic sequences of the eastern Bushveld Complex, Republic of South Africa. The holotype grain of driekopite (similar to 22x13 mu m) occurs in a complex, rounded aggregate similar to 120 mu m in diameter, in association with isoferroplatinum (Pt3Fe), hollingworthite (RhAsS), geversite (PtSb2), insizwaite (PtBi2), andrieslombaardite (RhSbS), stibiopalladinite (Pd5Sb2), sobolevskite (PdBi), possible tatyanaite (Pt9Cu3Sn4), osmium-bearing tulameenite (Pt2FeCu), and Pt-Fe alloy (similar to Pt2Fe). Driekopite appears slightly orange under reflected light compared to Pt-Fe alloys. It shows moderate to strong bireflectance, varying from light yellow to brownish yellow, no pleochroism or internal reflections, and moderate to strong anisotropism. The empirical formula, calculated from the average of six wavelengthdispersive spectrometry analyses made on five grains, on the basis of two atoms, is (Pt0.68Pd0.31Fe0.01)(Sigma 1.00)(Bi0.53Sb0.43As0.02 Sn0.02S0.01)(Sigma 1.01). The mineral is hexagonal, space group P63/mmc (#194) with the refined unit-cell dimensions a = 4.1993(5), c = 5.6194(6) degrees A, V = 85.82 degrees A 3, Z = 2, and D-calc - 12.91 g/cm(3). Driekopite is isostructural with NiAs, with mixed compositions of Pt and Pd at the 2a site (0.55:0.45, respectively) and Bi and Sb at the 2c site (0.63:0.37, respectively). Its crystal structure was refined to wR = 6.3% using 13 unique Laue reflections obtained using synchrotron radiation. The six strongest lines for the powder X-ray diffraction pattern calculated from the crystal structure refined from synchrotron data is [d in degrees A (I) (hkl)]: 3.0531 (92) (101), 2.2234 (100) (102), 2.0997 (77) (2 (1) over bar0, 1.5266 (28) (202), 1.2347 (24) similar to 12THORN, 1.1676 (18) o2 14+/-. The holotype grain of driekopite is observed to be paragenetically later than isoferroplatinum and hollingworthite and is considered to be synformational with Bi-bearing geversite, insizwaite, andrieslombaardite, and sobolevskite. The entire aggregate containing these platinum-group minerals is overgrown by a rim of tulameenite and Pt-Fe alloy (similar to Pt2Fe), indicating they are paragenetically the last minerals to form. Experiments designed to synthesize PtBi over the range of 200 to 500 8C were all successful. Synthetic PtBi melts congruently at 765 degrees C, suggesting that driekopite likely crystallized at sub-magmatic temperatures.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10504 - Mineralogy

Project

<a href="/en/project/GA22-26485S" target="_blank" >GA22-26485S: Synthetic platinum-group minerals and their applications</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2023

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

CANADIAN JOURNAL OF MINERALOGY AND PETROLOGY

ISSN

2817-1713

e-ISSN

2817-1713

Volume of the periodical

61

Issue of the periodical within the volume

3

Country of publishing house

CA - CANADA

Number of pages

11

Pages from-to

537-547

UT code for WoS article

001068615500005

EID of the result in the Scopus database

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