Orthocuproplatinum, Pt3Cu, a new mineral from the Lubero region, North Kivu, Democratic Republic of the Congo

0509552 - GLÚ 2020 RIV AT eng J - Journal Article
Cabral, A. R. - Skála, Roman - Vymazalová, A. - Maixner, J. - Stanley, C.J. - Lehmann, B. - Jedwab, J.
Orthocuproplatinum, Pt3Cu, a new mineral from the Lubero region, North Kivu, Democratic Republic of the Congo.
Mineralogy and Petrology. Roč. 113, č. 4 (2019), s. 527-532. ISSN 0930-0708. E-ISSN 1438-1168
Institutional support: RVO:67985831
Keywords : Orthocuproplatinum * Lubero * North Kivu * Democratic Republic of the Congo
OECD category: Mineralogy
Impact factor: 1.461, year: 2019
Method of publishing: Limited access
https://link.springer.com/article/10.1007%2Fs00710-019-00663-1

Orthocuproplatinum,Pt₃Cu,isanewmineralfromtheLuberoregionofNorthKivu,DemocraticRepublicoftheCongo.The mineral, which has a synthetic analogue, occurs as a 1.5-mm-long alluvial grain in a heavy-mineral concentrate, together with the holotype specimen of kitagohaite, Pt7Cu. The grain of orthocuproplatinum has a rim of hongshiite, PtCu, and abundant inclusions of calcite. Opaque and metallic, orthocuproplatinum has a whitish colour in reflected light and slightly perceptible anisotropy. The crystal structure of orthocuproplatinum is orthorhombic, space group Cmmm. Its unit-cell parameters: a =7.681(1)Å, b = 5.4318(8) Å, c = 2.7502(4) Å, V = 114.74(3) Å3, Z = 2. The calculated density is 17.866 g cm⁻³. The strongest diffraction lines are [d in Å(I)]: 2.337 (11), 2.236 (100), 2.217 (97), 1.932 (61), 1.920 (30), 1.362 (36), 1.169 (24), 1.161 (23). The Vickers hardness is 243 kg mm⁻² (VHN₂₅), corresponding to a Mohs hardness of 4. The empirical formula of orthocuproplatinum, calculated from a mean value of 12 electron-probe microanalyses that gave 12.9 wt% Cu and 87.3 wt% Pt, is Pt,sub.2.76Cu_1.24 on the basis of 4 atoms.
Permanent Link: http://hdl.handle.net/11104/0300344