ALBERT

Description: Mambertiite, BiMo 5+ 2.80 O 8 (OH), is a new mineral identified in small vugs of quartz veins from Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy. It occurs as pale yellow {001} tabular crystals, up to 1 mm in length and few mm thick, with adamantine lustre. Mambertiite is brittle, with a conchoidal fracture. It is associated with ferrimolybdite, muscovite, quartz, sardignaite, and wulfenite. Electron microprobe data (wt% – mean of 12 spot analyses) are: Mo 2 O 5 59.59, Bi 2 O 3 36.96, WO 3 2.03, H 2 O calc 1.48, sum 100.06. On the basis of 9 O atoms per formula unit, the empirical formula is Bi 0.99 (Mo 5+ 2.74 W 0.05 ) 2.79 O 7.97 (OH) 1.03 . Infrared spectra showed absorption bands consistent with the occurrence of OH – groups. Mambertiite is triclinic, space group $$P\overline{1}$$ , with a = 5.854(2), b = 9.050(3), c = 7.637(3) Å, α = 112.85(1), β = 102.58(1), = 90.04(1)°, V = 362.3(2) Å 3 , Z = 2. The crystal structure of mambertiite was solved and refined down to R 1 = 0.050 on the basis of 2019 observed [ F o 〉 4( F o )] reflections. It is composed by eight-fold coordinated Bi-centred polyhedra and five independent Mo-centred octahedra. Among the latter, two are completely occupied by molybdenum, whereas the remaining three are only partially occupied. Two kinds of ( $$10\overline{1}$$ ) layers occur in mambertiite, alternating along [ $$10\overline{1}$$ ]*: one is composed by Bi-centered polyhedra and the two partially occupied Mo4 and Mo5 sites, whereas the other is composed by the zigzag chains, running along c , formed by the fully occupied Mo1 and Mo2 sites, and the partially occupied Mo3 site. Mambertiite is structurally related to gelosaite, BiMo 6+ 2 O 7 (OH) · H 2 O; their relationships can be conveniently described through the OD theory. Mambertiite is the fourth known mineral with Bi and Mo as essential components. Its name honours the Italian mineral collector Marzio Mamberti (b. 1959) for his contribution to the knowledge of the Sardinian mineralogy. The mineral and its name have been approved by the IMA CNMNC (No. 2013–098).

Description: Cossaite, ideally (Mg0.5,?)Al6(SO4)6(HSO4)F6·36H2O, was found in the altered pyroclastic breccia of an active fumarole (T about 350°C) located at the rim of the La Fossa crater, Vulcano Island, Aeolian archipelago, Sicily, Italy. Cossaite is trigonal, space group R3I, with a = 22.010(2), c = 9.238(1) Å, V = 3875.6(6) Å3, Z = 3. It forms stout prismatic hexagonal crystals up to 100 µm in size, terminated by rhombohedral faces, and is associated with thermessaite, vlodavetsite, sassolite and salammoniac. Cossaite is colourless to white, the streak is white and the lustre vitreous. It is not fluorescent in either long-wave or short-wave ultraviolet radiation. The calculated density is 2.075 g cm-3. The mean refractive index nobs is 1.49(1) (589 nm). Chemical analysis gave MgO 1.4, Al2O3 19.5, SO3 34.7, F 5.7, (H2O 40.85, from structure refinement), O=F -2.4, total 99.75 wt.%, corresponding to the empirical formula Mg0.56Al6.19S7.01H73.37F4.85O65.15 calculated on the basis of 70 oxygen plus fluorine atoms. The strongest six lines in the X-ray powder diffraction pattern [dobs(Å) (I) (hkl)] are: 4.15 (100) (140), 3.87 (70) (32I2), 11.00 (50) (110), 4.58 (25) (131), 2.770 (20) (3I33), 2.166 (20) (1I8I1). The crystal structure was refined to a final R index of 0.0349. It contains octahedral [Al(H2O)5F]2+ cations and sulphate anions interacting via hydrogen bonds to form channels running along [001], where disordered [Mg(H2O)6]2+ cations and hydrogensulphate anions are hosted.

Description: 〈span〉The new mineral sbacchiite (IMA 2017-097), Ca〈sub〉2〈/sub〉AlF〈sub〉7〈/sub〉, was found in a fossil fumarole (1944 eruption, 〈span〉T〈/span〉 ≈ 80 °C) at the rim of the crater of the Vesuvius volcano, Napoli, Italy, associated with gearsksutite, usovite, creedite and opal. It forms elongated crystals up to about 60 μm in length. On the basis of powder X-ray diffraction data and chemical analysis, the mineral was recognized to be identical to the corresponding synthetic phase. Crystals are transparent or translucent and colourless, with vitreous lustre and white streak. The tenacity is brittle. The measured density is 3.08(2) g/cm〈sup〉3〈/sup〉, the calculated density is 3.116 g/cm〈sup〉3〈/sup〉. The empirical formula, (based on 10 atoms per formula unit, 〈span〉apfu〈/span〉) is Ca〈sub〉2.02〈/sub〉Mg〈sub〉0.03〈/sub〉Al〈sub〉0〈/sub〉.〈sub〉99〈/sub〉F〈sub〉6.97〈/sub〉. Sbacchiite is orthorhombic, space group 〈span〉Pnma〈/span〉, with 〈span〉a〈/span〉 = 7.665(2), 〈span〉b〈/span〉 = 6.993(1), 〈span〉c〈/span〉 = 9.566(2) Å, 〈span〉V〈/span〉 = 512.2(2) Å〈sup〉3〈/sup〉 and 〈span〉Z〈/span〉 = 4. The eight strongest X-ray powder diffraction lines are [〈span〉d〈/span〉〈sub〉obs〈/sub〉 Å(〈span〉I〈/span〉)(〈span〉hkl〈/span〉)]: 3.840(45)(200), 3.563(85)(201), 3.499(100)(020), 2.899(55)(013), 2.750(30)(212), 2.281(20)(104), 2.255(52)(302) and 2.173(36)(131). The structure was refined to 〈span〉R〈/span〉 = 0.0479 for 457 reflections with 〈span〉I〈/span〉 〉 2σ(〈span〉I〈/span〉). The asymmetric unit contains one Al〈sup〉3+〈/sup〉 and two independent Ca〈sup〉2+〈/sup〉 cations and five fluorine anions. Aluminium is octahedrally coordinated by six fluorine atoms; the arrangement of F around the 7-coordinated Ca(1) conforms to a distorted pentagonal bipyramid and that around Ca(2) to a very distorted polyhedron (in 7 + 1 coordination). All the fluorine atoms are threefold coordinated. The structure framework shows “isolated” [AlF〈sub〉6〈/sub〉] octahedra, whereas the coordination polyhedra around Ca are linked by common edges [sequence: Ca(1)–Ca(2)–Ca(1)…] along [010] and the same holds for the connection along [001]. Along [100], however, only the pentagonal bipyramids around Ca(1) are connected by bridging corners.〈/span〉

Description: The new mineral argesite, ammonium bismuth chloride (NH 4 ) 7 Bi 3 Cl 16 , was found in a medium-temperature (~250 °C) active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. The mineral occurs on a pyroclastic breccia as pale-yellow crystals up to 0.15 mm in length, in association with bismuthinite, adranosite, brontesite, demicheleite-(Br), demicheleite-(Cl), and panichiite. Argesite is trigonal, space group: R c (no. 167) with Z = 18; the unit-cell parameters are (single-crystal data): a = 13.093(1), c = 102.682(1) Å, and V = 15245(2) Å 3 . The six strongest reflections in the X-ray powder diffraction pattern are: [ d obs (Å) ( I ) ( hkl )] 3.164 (100) (0 3 18), 3.808 (44) ( 2 20), 2.742 (78) ( 4 21), 6.14 (16) ( 2 6), 1.906 (16) (0 0 $$\overline{54}$$ ), 1.686 (13) ( 6 34). The mineral is uniaxial (–), with = 1.731(2), = 1.725(2) (589 nm). The IR spectrum shows absorptions at 3188(vs), 3060(s), and 1397(vs) cm –1 , in agreement with the presence of the ammonium ion. Chemical analyses obtained by EDS electron microprobe gave (average wt%) Bi 42.26, Cl 32.57, Br 13.06, I 0.95, K 2.46, Tl 0.88, NH 4 7.82 (by difference) total 100.00, corresponding to the empirical formula: [(NH 4 ) 6.29 K 0.91 Tl 0.06 ] 7.26 Bi 2.93 (Cl 13.33 Br 2.37 I 0.11 ) 15.81 . The measured density is 2.88(1) g/cm 3 . The structure was refined, using single-crystal diffraction data, to a final R = 0.0345 for 1289 independent observed reflections [ I 〉 2( I )]. It contains Bi 2 Cl 10 4– and BiCl 6 3– anions where the Bi atoms are octahedrally coordinated, and NH 4 + cations are partially replaced by K + and Tl + ions.

Description: The new minerals d'ansite-(Mn), Na21Mn2+ (SO4)10Cl3, and d'ansite-(Fe), Na21Fe2+ (SO4)10Cl3, occur as encrustations in fumaroles at Vesuvius, Naples, Italy and La Fossa crater, Vulcano, Aeolian Islands, Italy, respectively. Both minerals are cubic and crystallize in space group I4İ3d. D'ansite-(Mn) forms colourless translucent tristetrahedral crystals up to 0.2 mm on edge; d'ansite-(Fe) forms aggregates of colourless to white complex isometric crystals of about the same size. Chemical analyses obtained by energy-dispersive spectrometry on an electron microprobe gave the following mean compositions: d'ansite-(Mn), Na2O 39.37, MnO 3.46, MgO 0.13, SO3 49.99, Cl 6.36, O=Cl −1.44, total 97.87 wt.%, corresponding to an empirical formula, on the basis of 43 anions, of Na ( Mg0.05)Σ0.84S10.13O40.09Cl2.91; and d'ansite-(Fe), Na2O 39.12, FeO 4.18, MgO 0.12, SO3 49.91, Cl 6.81, O=Cl −1.54, total 98.60 wt.%, corresponding to an empirical formula of Na20.42( Mg0.05)Σ0.99S10.08O39.89Cl3.11. The six strongest reflections in the X-ray powder diffraction pattern of d'ansite-(Fe) [listed as dobs(Å) (I) (hkl)] are as follows: 2.807(100)(044), 2.570(37)(235), 1.714(29)(129), 3.384(27)(233), 3.113(26)(134), 2.108(15)(237). The unit-cell parameters obtained from single-crystal data are 15.9291(9) and 15.882(3) Å for d'ansite-(Mn) and d'ansite-(Fe), respectively. The structure of both minerals was refined, using single-crystal diffraction data, to final R parameters of 0.0309 and 0.0336 on reflections with I 〉 2σ(I). The structure contains three independent Na sites, one of which is partially occupied by Mn2+ or Fe2+, two independent sulfate anions and one chlorine site.

Description: The new mineral aluminopyracmonite, ideally (NH 4 ) 3 Al(SO 4 ) 3 , was found in a medium-temperature (~250°C) intracrater active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as colourless to white prismatic crystals up to 0.2 mm long, in association with adranosite, mascagnite, alunite and salammoniac. The mineral is identical to the synthetic compound (NH 4 ) 3 Al(SO 4 ) 3 . It is trigonal, space group: R 3I (no. 148) with a = 15.0324(8), c = 8.8776(5) Å, V = 1737.3(2) Å 3 and Z = 6. The six strongest reflections in the X-ray powder diffraction pattern are: [ d obs in Å( I )( hkl )] 3.336(100)(131), 7.469(62)(1 1 0), 3.288(60)(122), 4.289(45)(2I 31), 2.824(29)(3I 5 1), 4.187(27)(012). The empirical formula based on 12 anions is [(NH 4 ) 2.89 K 0.10 ] 2.99 (Al 1.18 Fe 0.01 ) 1.19 S 2.91 O 12 , and the simplified formula (NH 4 ,K) 3 Al(SO 4 ) 3 . The measured density is 2.12(1) g/cm 3 , calculated density 2.143 g/cm 3 . The mineral is uniaxial(–) with = 1.545(3) and = 1.532(3) ( = 589 nm). Using single-crystal diffraction data, the structure was refined to a final R ( F ) = 0.0258 for 998 independent observed reflections [ I 〉 2( I )]. In spite of having unit-cell parameters comparable with those of pyracmonite, the two minerals are not isostructural; the difference is related to a disordered conformation of the sulfate anions about the two independent Al 3+ ions in aluminopyracmonite.

Description: The new mineral adranosite-(Fe), ideally (NH 4 ) 4 NaFe 2 (SO 4 ) 4 Cl(OH) 2 , is the Fe 3+ -analogue of adranosite. It was found on a pyroclastic breccia in two different fumaroles at "La Fossa" crater of Vulcano, Aeolian Islands, Italy, and corresponds to an anthropogenic product previously observed in a burning coal dump at the Anna mine, near Aachen, Germany. The mineral is tetragonal, space group I 4 1 / acd (no. 142), with a = 18.261(2), c = 11.562(1) Å, V = 3855.5(7) Å 3 (single-crystal data), and Z = 8. The six strongest reflections in the X-ray powder diffraction pattern are [ d obs in Å ( I )( hkl )]: 9.134(100)(020), 4.569(83)(040), 3.047(79)(152), 6.462(36)(220), 3.232(29)(251), and 2.891(11)(004). The average chemical composition of the holotype is (wt.%): Na 2 O 5.01, Fe 2 O 3 15.77, Al 2 O 3 5.11, K 2 O 0.82, (NH 4 ) 2 O 15.76, SO 3 50.96, Cl 3.71, H 2 O 2.75, –O=Cl–0.84, total 99.05; the corresponding empirical formula is: [(NH 4 ) 3.89 K 0.11 ] 4.00 Na 1.04 [Fe 1.27 Al 0.64 ] 1.91 S 4.10 O 16.40 C l0.67 (OH) 1.96 . Adranosite-(Fe) forms aggregates of pale yellow acicular crystals up to 1 mm in length, the most common forms most probably being {100}, {110}, and {111}. The measured density is 2.18(1) g/cm 3 , and the calculated density is 2.195 g/cm 3 . Adranosite-(Fe) is uniaxial (–) with =1.58(1), =1.57(1) ( = 589 nm). Using single-crystal X-ray diffraction data from the holotype, the structure was refined to a final R ( F )= 0.0415 for 670 independent observed reflections [ I 〉 2(( I )]. Adranosite-(Fe) is isostructural with its Al-analogue adranosite and contains NaO 4 Cl 2 square tetragonal bipyramids, linked through their opposite Cl corners and helicoidal chains with composition [FeO 4 (OH) 2 SO 4 ] n , both extending along [001]. The framework resulting from the sharing of the sulfate ions between the different chains displays cages in which the nine-coordinated hydrogen-bonded NH 4 + ions are hosted.

Description: The new mineral therasiaite, ideally (NH 4 ) 3 KNa 2 Fe 2+ Fe 3+ (SO 4 ) 3 Cl 5 , was found in a medium-temperature (~250°C) intracrater active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as brown to dark brown equant to short prismatic crystals up to 0.1 mm in length, in association with salammoniac, kremersite and adranosite. The mineral is monoclinic, space group: Cc (no. 9) with a = 18.284(4), b = 12.073(2), c = 9.535(2) Å, β = 108.10(3)°, V = 2000.6(7) Å 3 and Z = 4. The six strongest reflections in the X-ray powder diffraction pattern are: [ d obs in Å( I )( h k l )] 2.812(100)(2I 2 3), 2.664(77)(5I 1 3), 3.297(28)(3 3 1I), 3.208(14)(5I 1I 2), 3.008(12)(0 4 0), 2.942(11)(3 3 1). The empirical formula (based on 17 anions per formula unit (p.f.u.)) is (NH 4 ) 2.68 K 1.32 Na 2.04 Fe 1.76 Al 0.12 Mn 0.12 S 2.98 O 11.95 Cl 5.05 . The measured density is 2.41(1) g cm –3 , d calc = 2.395 g cm –3 . The mineral is biaxial (–) with α= 1.585(3) β = 1.615(3) and = 1.630(3) (white light). Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.0240 for 5574 independent observed reflections [ I 〉 2( I )]. The structure of therasiaite displays a novel topology and contains two independent, distorted octahedral Fe sites, with the Fe atoms in oxidation state 3+ and 2+, respectively, each surrounded by three Cl atoms and three oxygens of the sulfate ions. The Fe octahedra and the three independent sulfate anions are connected to form chains running along [001]. Voids between the chains are occupied by three independent ammonium ions (partially replaced by K + ), one K + and two Na + ions. The formula resulting from the structure refinement is [(NH 4 ) 2.25 K 0.75 ]KNa 2 Fe 2 (SO 4 ) 3 Cl 5 .

Description: The new mineral therasiaite, ideally (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5, was found in a mediumtemperature (∼250°C) intracrater active fumarole at La Fossa crater, Vulcano, Aeolian Islands, Sicily, Italy. It occurs on a pyroclastic breccia as brown to dark brown equant to short prismatic crystals up to 0.1 mm in length, in association with salammoniac, kremersite and adranosite. The mineral is monoclinic, space group: Cc (no. 9) with a = 18.284(4), b = 12.073(2), c = 9.535(2) Å, β = 108.10(3)°, V = 2000.6(7) Å3 and Z = 4. The six strongest reflections in the X-ray powder diffraction pattern are: [dobs in Å(I)(hkl)] 2.812(100)(23), 2.664(77)(13), 3.297(28)(33), 3.208(14)(2), 3.008(12)(040), 2.942(11)(331). The empirical formula (based on 17 anions per formula unit (p.f.u.)) is (NH4)2.68K1.32Na2.04Fe1.76Al0.12Mn0.12S2.98O11.95Cl5.05. The measured density is 2.41(1) g cm−3, dcalc = 2.395 g cm−3. The mineral is biaxial (−) with α= 1.585(3) β = 1.615(3) and γ = 1.630(3) (white light). Using single-crystal diffraction data, the structure was refined to a final R(F) = 0.0240 for 5574 independent observed reflections [I 〉 2σ(I)]. The structure of therasiaite displays a novel topology and contains two independent, distorted octahedral Fe sites, with the Fe atoms in oxidation state 3+ and 2+, respectively, each surrounded by three Cl atoms and three oxygens of the sulfate ions. The Fe octahedra and the three independent sulfate anions are connected to form chains running along [001]. Voids between the chains are occupied by three independent ammonium ions (partially replaced by K+), one K+ and two Na+ ions. The formula resulting from the structure refinement is [(NH4)2.25K0.75]KNa2Fe2(SO4)3Cl5.

Description: The new minerals d'ansite-(Mn), Na21Mn2+(SO4)10Cl3, and d'ansite-(Fe), Na21Fe2+(SO4)10Cl3, occur as encrustations in fumaroles at Vesuvius, Naples, Italy and La Fossa crater, Vulcano, Aeolian Islands, Italy, respectively. Both minerals are cubic and crystallize in space group I3d. D'ansite-(Mn) forms colourless translucent tristetrahedral crystals up to 0.2 mm on edge; d'ansite-(Fe) forms aggregates of colourless to white complex isometric crystals of about the same size. Chemical analyses obtained by energy-dispersive spectrometry on an electron microprobe gave the following mean compositions: d'ansite-(Mn), Na2O 39.37, MnO 3.46, MgO 0.13, SO3 49.99, Cl 6.36, O=Cl–1.44, total 97.87 wt.%, corresponding to an empirical formula, on the basis of 43 anions, of Na20.61 (Mn2+0.79Mg0.05)Σ0.84S10.13O40.09Cl2.91; and d'ansite-(Fe), Na2O 39.12, FeO 4.18, MgO 0.12, SO3 49.91, Cl 6.81, O=Cl –1.54, total 98.60 wt.%, corresponding to an empirical formula of Na20.42(Fe2+0.94Mg0.05)Σ0.99S10.08O39.89Cl3.11. The six strongest reflections in the X-ray powder diffraction pattern of d'ansite-(Fe) [listed as dobs(Å) (I) (hkl)] are as follows: 2.807(100)(044), 2.570(37)(235), 1.714(29)(129), 3.384(27)(233), 3.113(26)(134), 2.108(15)(237). The unit-cell parameters obtained from single-crystal data are 15.9291(9) and 15.882(3) Å for d'ansite-(Mn) and d'ansite-(Fe), respectively. The structure of both minerals was refined, using single-crystal diffraction data, to final R parameters of 0.0309 and 0.0336 on reflections with I 〉 2σ(I). The structure contains three independent Na sites, one of which is partially occupied by Mn2+ or Fe2+, two independent sulfate anions and one chlorine site.