The new mineral, heimaeyite, was found among the fumarolic encrustations collected on Eldfell volcano, on the island of Heimaey, Iceland. The mineral formed as microscopic rounded aggregates (<50 m) and rounded grains (<10 m) mixed with tiny needles of koryakite and a mineral phase with an NaMgAl(SO4)(3) composition. It was formed in scoria consisting of anhydrite, hematite, and cristobalite. Other associated minerals are tamarugite, hexahydrite, l & ouml;weite, and langbeinite. Heimaeyite is orange with a yellowish streak. It is translucent with a vitreous lustre. The calculated density is 2.783 g cm(-3). The chemical analysis gives a composition of Na2.93Al0.82Fe0.25S2.99O12.05. The ideal formula is Na3Al(SO4)(3) with 10 % to 25 % replacement of Al with Fe. Single-crystal X-ray diffraction analysis shows that it is trigonal and has a space group of with unit cell parameters of a=13.4326(9) & Aring;, c=8.9818(7) & Aring;, V=1403.5(2) & Aring;(3), and Z=6. The X-ray powder diffraction resembles that of Na3V(SO4)(3) (PDF 39-0243), with which it is isostructural. They both belong to the K7Nb(SO4)(6) structure type. In the crystal structure, the octahedral coordinations of the cation (in heimaeyite this is Al) are connected by sulfate tetrahedra in a "pin-wheel" arrangement into chains extending along [001]. The chains are interconnected by [NaO6] distorted trigonal prism coordinations. Fe substitutes for Al in the larger of the two symmetry-independent octahedral sites. Synthetic pure Na3Al(SO4)(3) was prepared through a solid-state reaction at 550 degrees C, and its structure was refined by the Rietveld method. It shows a smaller difference in size between the two octahedral sites than the natural sample.

Baliczunicite, ideally Bi2O(SO4)(2), is a new mineral found as a high-temperature fumarole sublimate (T = 600 degrees C) at La Fossa crater, Vulcano, Aeolian Islands, Italy. It occurs as aggregates of mu m-sized prismatic and elongated crystals (similar to 50 mu m across and up to 200 mu m long) associated with anglesite, leguernite, one other potentially new Bi-oxysulfate mineral, lillianite, galenobismutite, bismoclite, Cd-rich sphalerite, wurtzite, pyrite and pyrrhotite. Baliczunicite is colourless to white or pale brown, transparent and non-fluorescent. It has a vitreous lustre and a white streak. Electron microprobe analysis gives the following average chemical composition (wt.%): Bi2O3 68.68 and SO3 23.73, total 92.41. The empirical chemical formula, calculated on the basis of 9 anions p.f.u., is Bi1.99S2O9. The calculated density is 5.911 g/cm(3).Baliczunicite is triclinic, space group P (1) over bar, with a 6.7386(3), b 11.1844(5), c 14.1754(7) angstrom, alpha 80.082(2)degrees, beta 88.462(2)degrees, gamma 89.517(2)degrees, V = 1052.01(8) angstrom(3) and Z = 6. The six strongest reflections in the X-ray powder-diffraction data [d in angstrom (I) (hkl)] are: 3.146 (100) (033), 3.486 (21) (004), 3.409 (12) (0 (3) over bar1), 3.366 (7) (200), 5.562 (4) (111), 5.433 (4) ((1) over bar 11). Baliczunicite is the natural analogue of the stable low-temperature alpha form of synthetic Bi2O(SO4)(2). The name is in honour of Tonci Balic-Zunic (born 1952), Professor of Mineralogy at the Natural History Museum of the University of Cophenagen. Both the mineral and the mineral name have been approved by the IMA-CNMNC Commission (IMA2012-098).

The new mineral oskarssonite (IMA2012-088), with ideal formula AlF3, was found in August 2009 at the surface of fumaroles on the Eldfell volcano, Heimaey Island, Iceland (GPS coordinates 63 degrees 25'58.9''N 20 degrees 14'50.3''W). It occurs as sub-micron-sized crystals forming a white powder in association with anhydrite, bassanite, gypsum, jarosite, anatase, hematite, opal, ralstonite, jakobssonite and meniaylovite. Chemical analyses by energy-dispersive spectrometry with a scanning electron-microscope produced the following mean elemental composition: Al, 31.70; F, 58.41; O, 9.22; total 99.33 wt.%. The empirical chemical formula is AlF2.6(OH)(0.5) which suggests partial substitution of F by OH. Oskarssonite is rhombohedral, space group R (3) over barc, with a(h) = 4.9817(4) angstrom, c = 12.387(1) angstrom, V-uc = 266.23(5) angstrom(3), Z = 6. The five strongest lines in the powder diffraction diagram [d in angstrom (I) (hkl)] are as follows: 3.54 (100) (012), 2.131 (13) (113), 1.771 (20) (024), 1.59 (15) (116), 1.574 (10) (122). Rietveld refinement confirms the identity of oskarssonite with the synthetic rhombohedral form of AlF3. Its structure can be described as a rhombohedral deformation of the idealized cubic perovskite-type octahedral framework of corner-sharing AlF6 groups. Oskarssonite appears in the surface part of the fumaroles where fluorides are abundant. At greater depths (below 10 cm) sulfates dominate among the fumarolic minerals. In accordance with its occurrence, we surmise that oskarssonite forms in the later stages of the fumarolic activity in an environment poor in alkalies and Mg. Ralstonite (NaxMgxAl1-xF3(H2O)(y)), which, unlike oskarssonite, contains Na and Mg as important constituents, dominated in the first-formed fumaroles, but now, 41 years after the eruption of Eldfell, is only a minor phase. The new mineral is named after the Icelandic volcanologist Niels Oskarsson.

The new mineral jakobssonite, ideally CaAlF5, was first found in crusts collected in 1988 from a fumarole on the Eldfell volcano, Heimaey Island, Iceland. It was subsequently found in similar crusts collected in 1991 from a fumarole on the Hekla volcano, Iceland. It is associated with leonardsenite (IMA2011-059), ralstonite, heklaite, anhydrite, gypsum, jarosite, hematite, opal and several fluoride minerals that have not been fully characterized. Jakobssonite occurs as soft white fragile crusts of acicular crystals <50 mu m long. Its calculated density is 2.89 g cm(-3). Chemical analyses by energy-dispersive spectrometry on a scanning electron microscope produced a mean elemental composition as follows: Ca, 18.99; Al, 18.55; Mg, 1.33; Na, 0.33; F, 50.20; O, 10.39; total 99.79 wt.%. The empirical chemical formula, calculated on the basis of 7 atoms per formula unit with all of the oxygen as OH, is (Ca0.73Mg0.09Na0.02)(Sigma 0.84)Al1.06F4.09(OH)(1.01). Jakobssonite is monoclinic, space group C2/c, with a = 8.601(1), b = 6.2903(6), c = 7.2190(7) angstrom, beta = 114.61(1)degrees, V = 355.09(8) angstrom(3) and Z = 4. The crystal structure contains chains of [AlF6] octahedra which run parallel to the c axis. These chains are interconnected by chains of [CaF7] pentagonal bipyramids. Jakobssonite is isostructural with several other (CaMF5)-F-III compounds. The eight strongest lines in the powder diffraction diagram [d in angstrom (I) (hkl)] are as follows: 4.91 (18) (110), 3.92 (76) (200), 3.15 (68) (020), 3.13 (100) (1<(1)over bar>(2) over bar), 2.27 (22) (2 (2) over bar(2) over bar), 1.957 (21) (400), 1.814 (20) (1 (3) over bar(2) over bar), 1.805 (22) (20 (4) over bar). The chemical and crystal-structure analyses of jakobssonite are similar to synthetic CaAlF5 with minor substitutions of light elements (e.g. Na) or vacancies for Ca, and OH for F.

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Heklaite, with the ideal formula KNaSiF6, was found among fumarolic encrustations collected in 1992 on the Hekla volcano, Iceland. Heklaite forms a fine-grained mass of micron- to sub-micron-sized crystals intimately associated with malladrite, hieratite and ralstonite. The mineral is colourless, transparent, non-fluorescent, has a vitreous lustre and a white streak. The calculated density is 2.69 g cm(-3). An SEM-EDS quantitative chemical analysis shows the following range of concentrations (wt.%): Na 11.61-12.74 (average 11.98), K 17.02-18.97 (average 18.29), Si 13.48-14.17 (average 13.91), F 54.88-56.19 (average 55.66). The empirical chemical formula, calculated on the basis of 9 a.p.f.u., is Na1.07K0.96Si1.01F5.97. X-ray powder diffraction indicates that heklaite is orthorhombic, space group Pnma, with the following unit-cell parameters: a = 9.3387(7) angstrom, b = 5.5032(4) angstrom, c = 9.7957(8) angstrom, V = 503.43(7) angstrom(3), Z = 4. The eight strongest reflections in the powder diffraction pattern [d in angstrom (I/I-0) (hkl)] are: 4.33 (53) (102); 4.26 (56) (111); 3.40 (49) (112); 3.37 (47) (202); 3.34 (100) (211); 2.251 (27) (303); 2.050 (52) (123); 2.016 (29) (321). On the basis of chemical analyses and X-ray data, heklaite corresponds to the synthetic compound KNaSiF6. The name is for the type locality, the Hekla volcano, Iceland.

Crystals of challacolloite, KPb2Cl5, and hephaistosite, TlPb2Cl5, from volcanic sublimates formed on the crater rim of the “La Fossa Crater” at Vulcano, Aeolian Archipelago, Italy, were investigated. Chemical compositions were \({\left( {{\text{K}}_{{0.93}} {\text{Tl}}_{{0.02}} } \right)}_{{\Sigma = 0.95}} {\text{Pb}}_{{2.04}} {\left( {{\text{Cl}}_{{4.90}} {\text{Br}}_{{0.11}} } \right)}_{{\Sigma = 5.01}} \) and \({\text{Tl}}_{{0.94}} {\text{Pb}}_{{2.01}} {\left( {{\text{Cl}}_{{4.91}} {\text{Br}}_{{0.14}} } \right)}_{{\Sigma = 5.05}} \), respectively. Single crystal X-ray measurements showed monoclinic symmetry for both phases, space group P21/c, with the following unit-cell parameters: a = 8.8989(4), b = 7.9717(5), c = 12.5624(8) Å, β = 90.022(4)°, V = 891.2(1) Å3, Z = 4 (challacolloite) and a = 9.0026(6), b = 7.9723(6), c = 12.5693(9) Å, β = 90.046(4)°, V = 902.1(1) Å3, Z = 4 (hephaistosite). The structure refinements converge to R = 3.99% and R = 3.86%, respectively. The effects of Br↔Cl and K↔Tl substitutions on the structure of these natural compounds have been discussed.