JACUTINGAITE, Pt2HgSe3, A NEW PLATINUM-GROUP MINERAL SPECIES FROM THE CAUE IRON-ORE DEPOSIT, ITABIRA DISTRICT, MINAS GERAIS, BRAZIL

Phase relations in the Hg-Pd-Se system were studied by the evacuated silica glass tube technique. For kinetic reasons, experiments were performed in the range 350-400 ºC. We present here the 400 ºC condensed isothermal section for the Hg-Pd-Se system, based on literature data and on our experiments. Two ternary phases were known previously: Pd 8 Hg 3 Se 9 , which corresponds to tischendorfite, and Pd 2 HgSe 3 . We report here on a third phase, Pd 5 HgSe. Tischendorfite forms stable assemblages with palladseite (Pd 17 Se 15 ), tiemannite (HgSe), potarite (PdHg), and with the phase Pd 2 HgSe 3 . In turn, Pd 2 HgSe 3 forms stable assemblages with PdSe 2 (orthorhombic), palladseite (Pd 17 Se 15 ), tischendorfite (Pd 8 Hg 3 Se 9 ), and tiemannite (HgSe). The phase Pd 5 HgSe, stable near the Pd-rich corner of the system, forms stable assemblages with metallic Pd, PdHg (potarite), palladseite (Pd 17 Se 15 ), and other Pd-rich binary palladium selenides. Palladseite forms limited solidsolution and dissolves up to 4.15 at.% Hg at 350 ºC. This solid solution forms stable assemblages with Pd 8 Hg 3 Se 9 , PdSe 2 , and HgPd (potarite). There are no joins involving HgSe (tiemannite) and binary Pd selenides.

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“…This phase is a Pd analogue of jacutingaite (Pt 2 HgSe 3 ) recently described by Vymazalová et al (2012).…”

Section: Minerals In the Systemmentioning

confidence: 77%

THE SYSTEM Hg-Pd-Se AT 400 C: PHASE RELATIONS INVOLVING TISCHENDORFITE AND OTHER TERNARY PHASES

Drábek¹,

Vymazalová²,

Laufek³

2014

The Canadian Mineralogist

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“…Jacutingaite has a centrosymmetric trigonal structure, belonging to the space group P

\overset{3}{true}

m1 . Figure a shows the unit cell of 12 atoms, with two structural formulas ( Z =2).…”

Section: Resultsmentioning

confidence: 99%

“…Neither Raman nor X‐ray diffraction data is provided here for the only existing single specimen and small natural jacutingaite sample, which is deposited at the museum “Geosammlung” of the Technische Universität Clausthal, Germany. Electron backscattering diffraction was previously used to confirm the structural identity between the synthetic and natural jacutingaite sample, legitimating the use of the synthetic phase for further characterization …”

Section: Methodsmentioning

confidence: 99%

“…Jacutingaite (Pt 2 HgSe 3 ) is a layered platinum‐group mineral first observed in 2008, at the Itabira district, Minas Gerais, Brazil (a representation of its structure is shown in Figure ) . Subsequently, in 2012, a synthetic analogue was prepared, providing enough material for powder X‐ray diffraction . This material is receiving increasing attention due to the recent theoretical report showing that its two‐dimensional (2D) monolayer version behaves like a QSHI with a robust, record‐high topological gap of ∼0.5 eV.…”

Section: Introductionmentioning

confidence: 99%

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Raman spectrum of layered jacutingaite (Pt₂HgSe₃) crystals—Experimental and theoretical study

Longuinhos

Vymazalová

Cabral

et al. 2019

J Raman Spectroscopy

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Jacutingaite (Pt2HgSe3) is a recently discovered layered platinum‐group mineral. Recent experimental studies have shown that it displays the properties of a quantum spin Hall insulator (QSHI), and theoretical studies indicate that its two‐dimensional monolayer is a QSHI with a robust topological gap of ∼0.5 eV. Jacutingaite is thus promising for potential applications to nanoelectronics and spintronics. The Raman spectrum of three‐dimensional bulk jacutingaite and the symmetries of its vibrational modes, fundamental for understanding structural modifications of this material, are still unexplored. Here, we address the zone‐center Raman optical phonons of bulk jacutingaite by experiments, symmetry, and first‐principles calculations. The improved synthesis used here provided crystals of higher purity and of micrometer size, allowing the study of single crystals. Polarized Raman spectroscopy was used to assign the symmetries of nine out of the 11 Raman‐active modes expected by group theory and their respective selection rules. The calculated wavenumbers of the Raman‐active modes, in addition to their atomic displacements, are in very good agreement with experiments. In addition, we discuss the use of different exchange correlation functionals within density functional theory, as local functionals and nonlocal functionals that best describe van der Waals interactions. The influence of the inclusion of spin–orbit coupling on calculated vibrational phonon wavenumbers and lattice parameters is commented, and it was found that the local density approximation provides a good description. Our results are of paramount importance to further exploitation of the effects of jacutingaite's structural modifications to tune its properties, as well as for its structural, optical, electronic, mechanical, and thermal applications.

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“…The bonanza gold had prolific denominations, such as inficionado (i.e., infected) or podre (i.e., rotten), which described their quality, degraded by the presence of extraneous metals that were subsequently characterized as palladium and platinum (e.g., von Eschwege, 1833;Berzelius, 1835;Guerra, 2004). Recently, a new mineral, jacutingaite (Pt2HgSe3, Vymazalová et al, 2012), was defined from a jacutinga vein system at Itabira, a world-class Fe-ore district. The specular hematite-rich lodes hosting ouro preto are locally referred to as jacutinga, which occurs as veins that truncate the tectonic foliation of the host itabirite (Henwood, 1871;Hussak, 1904;Galbiatti et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

LATE CAMBRIAN Au-Pd MINERALIZATION AND Fe ENRICHMENT IN THE ITABIRA DISTRICT, MINAS GERAIS, BRAZIL, AT 496 Ma: CONSTRAINTS FROM U-Pb MONAZITE DATING OF A JACUTINGA LODE

et al. 2014

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Bonanza-style mineralization of palladiferous gold in specular hematite-rich lodes engendered the most important gold rush in Brazilian history, which took place at the end of the seventeenth century in the province that became known as Minas Gerais. The timing of this itabirite-hosted vein mineralization, locally referred to as jacutinga, is controversial; different views have ascribed jacutinga to one of the two orogenic events recorded in the Quadrilátero Ferrífero of Minas Gerais, the ~2.0 Ga Transamazonian event and the ~0.6 Ga Brasiliano event. This controversy is due mainly to the absence of reliable age data for hydrothermal minerals. Here we report the first U-Pb age for a jacutinga lode, obtained by laser ablation-sector field-inductively coupled plasmamass spectrometry (LA-SF-ICP-MS) on monazite grains recovered from the Conceição Fe-ore deposit within the Itabira district. The monazite analyses yield a precise Late Cambrian age of 495.6 ± 2.2 Ma, which is well within the time period between ca. 524 and 444 Ma, suggested by recently published geochronologic data on regionally distributed similar hydrothermal systems. The age of 496 Ma for the jacutinga monazite corroborates an orogen-scale hydrothermal overprint at later stages of the Brasiliano event. This hydrothermal overprint also affected surrounding Neoarchean rocks of the Minas Supergroup, as well as younger rocks of the southern Serra do Espinhaço, along the platiniferous Au-Pd belt of Minas Gerais.

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JACUTINGAITE, Pt2HgSe3, A NEW PLATINUM-GROUP MINERAL SPECIES FROM THE CAUE IRON-ORE DEPOSIT, ITABIRA DISTRICT, MINAS GERAIS, BRAZIL

Cited by 40 publications

References 13 publications

THE SYSTEM Hg-Pd-Se AT 400 C: PHASE RELATIONS INVOLVING TISCHENDORFITE AND OTHER TERNARY PHASES

THE SYSTEM Hg-Pd-Se AT 400 C: PHASE RELATIONS INVOLVING TISCHENDORFITE AND OTHER TERNARY PHASES

Raman spectrum of layered jacutingaite (Pt₂HgSe₃) crystals—Experimental and theoretical study

LATE CAMBRIAN Au-Pd MINERALIZATION AND Fe ENRICHMENT IN THE ITABIRA DISTRICT, MINAS GERAIS, BRAZIL, AT 496 Ma: CONSTRAINTS FROM U-Pb MONAZITE DATING OF A JACUTINGA LODE

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JACUTINGAITE, Pt2HgSe3, A NEW PLATINUM-GROUP MINERAL SPECIES FROM THE CAUE IRON-ORE DEPOSIT, ITABIRA DISTRICT, MINAS GERAIS, BRAZIL

Cited by 40 publications

References 13 publications

THE SYSTEM Hg-Pd-Se AT 400 C: PHASE RELATIONS INVOLVING TISCHENDORFITE AND OTHER TERNARY PHASES

THE SYSTEM Hg-Pd-Se AT 400 C: PHASE RELATIONS INVOLVING TISCHENDORFITE AND OTHER TERNARY PHASES

Raman spectrum of layered jacutingaite (Pt2HgSe3) crystals—Experimental and theoretical study

LATE CAMBRIAN Au-Pd MINERALIZATION AND Fe ENRICHMENT IN THE ITABIRA DISTRICT, MINAS GERAIS, BRAZIL, AT 496 Ma: CONSTRAINTS FROM U-Pb MONAZITE DATING OF A JACUTINGA LODE

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Raman spectrum of layered jacutingaite (Pt₂HgSe₃) crystals—Experimental and theoretical study