ALBERT

Description: The chemistry and crystal structure of a unique Zn-rich kupletskite: (K1.55Na0 .21Rb0.09Sr0.01)Σ1.86(Na0.82Ca0.18)Σ1.00(Mn4.72Zn1.66Na0.41Mg0.12)Σ7.00(Ti1.85Nb0.11Hf0.03)Σ1.99(Si7.99Al0.12)Σ8.11O26(OH)4(F0.77OH0.23)Σ1.00, from analkalin e pegmatite at Mont Saint-Hilaire, Quebec, Canada has been determined. Zn-rich kupletskite is triclinic,,a= 5.3765(4),b= 11.8893(11),c= 11.6997(10), α = 113.070(3), β = 94.775(2), γ = 103.089(3),R1 = 0.0570 for 3757 observed reflections withFo〉 4σ(Fo). From the single-crystal X-ray diffraction refinement, it is clear that Zn2+shows a preference for the smaller,trans M(4) site (69%), yet is distributed amongst all three octahedral sites coordinated by 4 O2−and 2 OH−[M(2) 58% andM(3) 60%]. Of note is the lack of Zn inM(1), the larger and least-distorted of the four crystallographic sites, with an asymmetric anionic arrangement of 5 O2−and 1 OH−. The preference of Zn for octahedral sites coordinated by mixed ligands (O and OH) is characteristic of its behaviour in alkaline systems, in contrast to granitic systems where Zn tends to favour [4]-coordinated, OH− and H2O-free sites with only one ligand species (O, S, Cl, B, I). In alkaline systems,[4]Zn is only present in early sphalerite or in late-stage zeolite-like minerals. The bulk of Zn in alkaline systems is present as discrete[6]Zn phases such as members of the astrophyllite, labuntsovite, milarite and nordite groups, a result of the formation of network-formingcomplexes inthe low-temperature, low-fS2, high-alkalinity and highly oxidizing systems.

Description: The new mineral mellizinkalite, K 3 Zn 2 Cl 7 , is found in the Glavnaya Tenoritovaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. Associated minerals are belloite, avdoninite, eriochalcite, sylvite, halite, carnallite, mitscherlichite, sanguite, chrysothallite, romanorlovite, gypsum, chlorothionite, kainite and earlier hematite, tenorite and chalcocyanite. Mellizinkalite occurs as irregularly shaped grains up to 0.5 mm across or crude elongated crystals up to 0.25 x 1.3 mm, their clusters and crusts up to 2 x 2 mm in area and up to 0.5 mm thick. The mineral is yellow-brown to reddish brown, transparent, with vitreous lustre. It is moderately brittle, slightly plastic. The Mohs’ hardness is ca. 2. Cleavage is not observed, the fracture is uneven. D meas = 2.46(2) and D calc = 2.49 3 g cm –3 . Mellizinkalite is optically biaxial (–), α = 1.556(5), β = 1.612(5), = 1.663(5) and 2 V meas = 85(5)°. The Raman spectrum is reported. The chemical composition (wt.%, electron-microprobe data) is: K 23.5, Rb 0.52, Mg 0.47, Cu 1.77, Zn 24.4, Cl 50.0, total 100.7. The empirical formula calculated on the basis of 12 atoms pfu is: (K 2.95 Rb 0.03 ) 2.98 (Zn 1.84 Cu 0.14 Mg 0.09 ) 2.07 Cl 6.95 . Mellizinkalite is triclinic, P $$\overline{1}$$ , a = 6.7737(4), b = 10.5715(13), c = 11.0730(9) Å, α = 117.930(10), β = 106.909(5), 90.389(8)°, V =660.61(10) Å 3 and Z =2. The strongest reflections of the X-ray powder pattern [ d ,Å ( I ) ( hkl )] are: 9.20(69)(001, 010, 0–11), 6.40(100)(100), 5.712(47)(–110, –1–11), 4.608(92)(002, 020), 3.499(55)(012), 3.473(73)(0–13, 0–31, 0–23), 3.393(66)(–201) and 3.075(49)(003). The crystal structure, solved from single-crystal X-ray diffraction data ( R = 0.065), is unique. It consists of alternating layers of different ZnCl 4 polyhedra. The Zn(1) cations are located in flat squares which are connected to each other via common Cl-Cl edges to form Zn 2 Cl 6 dimers, whereas Zn(2) cations occupy isolated tetrahedra. Potassium cations occupy sites between the layers of Zn-centred polyhedra. The mineral (IMA2014–010) is named from three Latin words, melli s – honey, zin cum and kal ium, alluding to its colour and species-defining cations, zinc and potassium.

Description: ‘Clinobarylite’, BaBe 2 Si 2 O 7 , was defined as a monoclinic dimorph of orthorhombic barylite. Subsequently, its crystal structure was also proved to be orthorhombic, differing from barylite in terms of the space group symmetry, Pmn 2 1 instead of Pmnb , and in unit-cell dimensions. Through the order-disorder (OD) theory, the polytypic relationships between ‘clinobarylite’ and barylite are described. ‘Clinobarylite’ corresponds to the MDO 1 polytype, with unit-cell parameters a = 11.650, b = 4.922, c = 4.674 Å, space group Pmn 2 1 ; barylite corresponds to the MDO 2 polytype, with a = 11.67, b = 9.82, c = 4.69 Å, space group Pmnb . The re-examination of the holotype specimen of ‘clinobarylite’ confirmed its orthorhombic symmetry. Its crystal structure has been refined starting from the atomic coordinates calculated for the MDO 1 polytype and the refinement converged to R 1 = 0.0144 for 929 observed reflections [ F o 〉 4 F o ]. Owing to their polytypic relationships, ‘clinobarylite’ and barylite should be conveniently indicated as barylite-1 O and barylite-2 O , respectively; the name ‘clinobarylite’ should be discontinued. This new nomenclature of the barylite polytypes has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 13-E).

Description: The new mineral chubarovite, KZn 2 (BO 3 )Cl 2 , was found in the sublimates of active fumaroles at the Second and First scoria cones of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. At the Second scoria cone it occurs in the Arsenatnaya fumarole (the holotype) with fluoborite, krasheninnikovite, sylvite, halite, langbeinite, aphthitalite, orthoclase, fluorophlogopite, hematite, and tenorite. At the First scoria cone, chubarovite is closely associated with sellaite, fluorite, anhydrite, halite, cotunnite, challacolloite, sofiite, and flinteite. Chubarovite forms hexagonal or trigonal lamellar to tabular crystals up to 1.5 mm across and up to 0.5 mm thick, with aggregates and crystal crusts up to 1 cm across. The major crystal form is {001}, and lateral faces are {101}, {102}, {103}, {100}, and {110}; twins of two types are observed. Chubarovite is transparent, colorless, with vitreous luster. It is flexible but not elastic. The Mohs hardness is ca . 2. Cleavage is (001) perfect, mica-like. D (meas.) is 2.68(2), D (calc.) is 2.716 g cm –3 . Chubarovite is optically uniaxial (–), with 1.541(2), 1.539(2). The infrared spectrum is given. Chemical data (wt.%, determined by electron-microprobe, boron by ICP OES) are: K 2 O 16.48, Rb 2 O 0.46, ZnO 53.96, B 2 O 3 10.98, Cl 24.48, –O=Cl 2 –5.53, total 100.83. The empirical formula, based on 5 (O+Cl) apfu , is: (K 1.05 Rb 0.01 ) 1.06 Zn 2.00 B 0.95 O 2.92 Cl 2.08 . Chubarovite is trigonal, R 32, a 4.9429(4), c 26.348(2) Å, V 557.50(8) Å 3 , and Z = 3. The strongest reflections of the powder X-ray diffraction pattern [ d ,Å( I )( hkl )] are: 8.79(100)(003), 4.394(43)(006), 4.225(25)(101), 4.074(91)(012), 3.590(90)(104), 3.324(30)(015), 2.470(67)(110), and 2.245(25)(1.0.10). Chubarovite has a novel structure type. Its crystal structure, solved from single-crystal X-ray diffraction data ( R = 0.020), is composed of layers of two types with an alternation along [001]. The anionic {Zn 2 (BO 3 )Cl 2 } – layer consists of flat triangular BO 3 groups sharing all O vertices with bases of ZnO 3 Cl tetrahedra. Each Cl atom is shared between one Zn-centered tetrahedron and three edge-connected KCl 6 octahedra belonging to the cationic layer formed by K + cations. The mineral is named in honor of the Russian mineralogist and physicist Valeriy M. Chubarov (born 1948).

Description: The new mineral kononovite, NaMg(SO 4 )F, the first sulphate member of the durangite (tilasite) group, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is closely associated with langbeinite, hematite, anglesite and euchlorine. Uklonskovite is a product of the supergene alteration of kononovite. The new mineral occurs as prismatic to thick tabular crystals up to 0.04 x 0.06 x 0.1 mm, isolated or, more typically, forming clusters or interrupted crusts up to several cm 2 in area and up to 0.05 mm thick overgrowing basalt scoria. Kononovite is white, transparent in tiny grains and translucent in blocky crystals, with vitreous lustre. It is brittle but with signs of weak plasticity; one direction of imperfect cleavage is observed. The Mohs’ hardness is ca. 3. D meas = 2.91(1), D calc = 2.945 g cm –3 . Kononovite is optically biaxial (+), α = 1.488(2), β = 1.491(2), = 1.496(2), 2 V m eas = 75(5)°. The IR spectrum is reported. The chemical composition (wt%, electron-microprobe data) is: Na 2 O 18.68, K 2 O 0.14, MgO 24.77, ZnO 0.28, PbO 0.10, SO 3 48.44, F 11.82, Cl 0.12, O = (F,Cl) – 5.00, total 99.35. The empirical formula calculated on the basis of 5 (O + F + Cl) anions pfu is: Na 0.99 K 0.01 Mg 1.01 Zn 0.01 S 0.99 O 3.97 F 1.02 Cl 0.01 . The strongest reflections of the powder X-ray diffraction pattern [ d ,Å( I )( hkl )] are: 4.766(38)(–111), 3.567(33)(021), 3.233(82)(–112), 3.210(55)(002), 3.041(100)(200), 2.589(53)(130), 2.571(38)(022) and 2.269(33)(131). Kononovite is monoclinic, space group C 2/ c [by analogy with synthetic NaMg(SO 4 )F which is practically identical to the mineral in its powder XRD pattern], a = 6.662(2), b = 8.584(3), c = 7.035(2) Å, β = 114.06(3)°, V = 367.4(1) Å 3 and Z = 4. The mineral is named in honour of the Russian mineralogist Oleg V. Kononov (born 1932), Moscow State University. Two types of fluorine mineralization in deposits of the Tolbachik fumaroles are discussed.

Description: Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals.