Karpenkoite, Co3(V2O7)(OH)2·2H2O, a cobalt analogue of martyite from the Little Eva mine, Grand County, Utah, USA

Abstract

Karpenkoite (IMA 2014-092), ideally Co 3 (V 2 O 7 )(OH) 2 ·2H 2 O, is a new divanadate mineral species, the cobalt analogue of martyite, found at the Little Eva mine, Grand County, Utah, USA. It occurs on sandstone matrix in close association with martyite, quartz, gypsum, baryte, roscoelite and an unidentified Al vanadate. Karpenkoite is a secondary mineral formed during the post-mining oxidation of corvusite and montroseite in a moist environment at ambient temperatures. The new mineral occurs as lamellar crystals, coarsely hexagonal or irregular in shape, typically curved. The crystals form rose-like clusters or globular aggregates up to 0.2 mm across. Karpenkoite is orange with pale yellow-orange streak. It is transparent with a vitreous luster. The mineral is brittle, with laminated fracture and perfect cleavage on {001}. The calculated density is 3.415 g cm

Microstructured layered-kagome BaCo3(VO4)2(OH)2 with variable crystallite size: alternative synthetic route and comparison with nanostructured samples

“…In this paper, we report an alternative synthetic strategy to obtain microstructured BaCo 3 (VO 4 ) 2 (OH) 2 via hydrothermal treatment of Co 3 V 2 O 7 (OH) 2 ·2H 2 O, which is the synthetic analogue of mineral karpenkoite, 19 in Ba(CH 3 COO) 2 aqueous solution. This synthetic route is inspired by previously published works that reported the preparation of vesignieite BaCu 3 (VO 4 ) 2 (OH) 2 by heating powders or crystals of volborthite Cu 3 V 2 O 7 (OH) 2 ·2H 2 O either at ambient pressure 20 or under hydrothermal conditions.…”

Precipitation Stripping of V(V) as a Novel Approach for the Preparation of Two-Dimensional Transition Metal Vanadates

“…On the contrary, slower addition led to purer materials and higher crystallinity. EDS element composition (Figure S1) indicated that the Co (II)/V atomic ratios were in good agreement ( [20], space group 164 (P-3m1). The mineral karpenkoite can be seen as orange lamellar crystals up to 0.05 mm, coarsely hexagonal or irregular in shape, and the crystals, usually curved, grow in rose-like clusters or globular aggregates.…”

“…The diffraction planes of the sample obtained over the reaction time of 1 h could be well indexed to cubic V 3 O 4 (Spacegroup No = 227, HermannMauguin = F4_1/d-32/m), as well as to the trigonal crystal form of karpenkoite, Co 3 (V 2 O 7 )(OH) 2 ·2H 2 O, a cobalt analogue of martyite, Zn 3 (V 2 O 7 )(OH) 2 (H 2 O) 2 [ 20 ], space group 164 (P-3m1). The mineral karpenkoite can be seen as orange lamellar crystals up to 0.05 mm, coarsely hexagonal or irregular in shape, and the crystals, usually curved, grow in rose-like clusters or globular aggregates.…”

Bakakinite, Ca2V2O7, a new mineral from fumarolic exhalations of the Tolbachik volcano, Kamchatka, Russia

“…Typically, pyrovanadates (and natural divanadates in general) are hydrous minerals formed in supergene environments or in late, low-temperature hydrothermal assemblages. Except for volborthite Cu 3 V 2 O 7 (OH) 2 ⋅2H 2 O (Kashaev and Bakakin, 1968; Vladimirova et al , 2021 and references therein) and the related minerals martyite Zn 3 V 2 O 7 (OH) 2 ⋅2H 2 O (Kampf and Steele, 2008) and karpenkoite Co 3 V 2 O 7 (OH) 2 ⋅2H 2 O (Kasatkin et al , 2015), there are fianelite Mn 2 (V,As) 2 O 7 ⋅2H 2 O (Brugger and Berlepsch, 1996), engelhauptite KCu 3 (V 2 O 7 )(OH) 2 Cl (Pekov et al , 2015), mesaite CaMn 2+ 5 (V 2 O 7 ) 3 ⋅12H 2 O (Kampf et al , 2017) and donowensite CaFe 3+ 2 (V 2 O 7 ) 2 ⋅3H 2 O (Kampf et al , 2022). For pintadoite the formula Ca 2 V 2 O 7 ⋅9H 2 O is suggested, however, this mineral is poorly studied and has the IMA status Q – questionable (Pasero, 2023).…”