Mineralogical Museum Research Articles

Magnesiovoltaite, K2Mg5Fe3+ 3Al(SO4)12·18H2O, a new mineral from the Alcaparrosa mine, Antofagasta region, Chile

Magnesiovoltaite, a new voltaite-group mineral, was discovered in the Alcaparrosa mine, Cerro Alcaparrosa, El Loa province, Antofagasta region, Chile, in two associations, one of which includes coquimbite, tamarugite, alum-(Na), rhomboclase, yavapaiite, voltaite and opal, and the other one is botryogen, opal, tamarugite, alum-(K), pickeringite, magnesiocopiapite, and jarosite. Magnesiovoltaite forms yellow, brownish-yellow or pale yellowish-greenish isometric crystals up to 2 mm across. The main crystal forms are {111} and {100}; the subordinate forms are {110} and {211}. The new mineral is brittle, with subconchoidal fracture; cleavage is not observed. Mohs’ hardness is 2½. D meas = 2.51(2) g/cm 3 , D calc = 2.506 g/cm 3 . Magnesiovoltaite is optically anomalously anisotropic, uniaxial with e = 1.584(2) and ω = 1.588(2), or biaxial (−) with α = 1.584(2), β = 1.587(2), and γ = 1.588 (2). Possible causes of the optical anomalies are discussed. The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, all iron is considered as Fe 3+ in accordance with Mossbauer data, H 2 O by gas chromatography of ignition products, wt. %): Na 2 O 0.13, K 2 O 4.64, MgO 9.13, MnO 1.73, ZnO 0.84, Al 2 O 3 2.47, Fe 2 O 3 13.36, SO 3 50.83, H 2 O 17.6, total 100.73. The empirical formula based on 66 O atoms per formula unit ( apfu ) is (K 1.85 Na 0.08 )(Mg 4.25 Mn 0.46 Zn 0.14 )Fe 3+ 3.14 Al 0.91 (SO 4 ) 11.91 (H 2 O) 18.325 O 0.035 . The simplified formula is K 2 Mg 5 Fe 3+ 3 Al(SO 4 ) 12 ·18H 2 O. The crystal structure has been refined to R = 3.2% using 1147 unique reflections with I > 2σ( I ). Magnesiovoltaite is cubic, Fd –3 c, a = 27.161(1) A, V = 20038(2) A 3 , and Z = 16. Magnesiovoltaite is isostructural with other cubic voltaite-group minerals. The strongest lines of the powder X-ray diffraction pattern [ d , A ( I , %) ( hkl )] are: 9.56 (29) (022), 6.77 (37) (004), 5.53 (61) (224), 3.532 (68) (137), 3.392 (100) (008), 3.034 (45) (048), 2.845 (30) (139). The type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia.

Mendigite, Mn2Mn2MnCa(Si3O9)2, a new mineral species of the bustamite group from the Eifel volcanic region, Germany

A new mineral, mendigite (IMA no. 2014-007), isostructural with bustamite, has been found in the In den Dellen pumice quarry near Mendig, Laacher Lake area, Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. Associated minerals are sanidine, nosean, rhodonite, tephroite, magnetite, and a pyrochlore-group mineral. Mendigite occurs as clusters of long-prismatic crystals (up to 0.1 × 0.2 × 2.5 mm in size) in cavities within sanidinite. The color is dark brown with a brown streak. Perfect cleavage is parallel to (001). D calc = 3.56 g/cm3. The IR spectrum shows the absence of H2O and OH groups. Mendigite is biaxial (–), α = 1.722 (calc), β = 1.782(5), γ = 1.796(5), 2V meas = 50(10)°. The chemical composition (electron microprobe, mean of 4 point analyses, the Mn2+/Mn3+ ratio determined from structural data and charge-balance constraints) is as follows (wt %): 0.36 MgO, 10.78 CaO, 37.47 MnO, 2.91 Mn2O3, 4.42 Fe2O3, 1.08 Al2O3, 43.80 SiO2, total 100.82. The empirical formula is Mn2.00(Mn1.33Ca0.67) (Mn0.50 2+ Mn0.28 3+ Fe0.15 3+ Mg0.07)(Ca0.80 (Mn0.20 2+)(Si5.57 Fe0.27 3+ Al0.16O18). The idealized formula is Mn2Mn2MnCa(Si3O9)2. The crystal structure has been refined for a single crystal. Mendigite is triclinic, space group $P\bar 1$ ; the unit-cell parameters are a = 7.0993(4), b = 7.6370(5), c = 7.7037(4) A, α = 79.58(1)°, β = 62.62(1)°, γ = 76.47(1)°; V = 359.29(4) A3, Z = 1. The strongest reflections on the X-ray powder diffraction pattern [d, A (I, %) (hkl)] are: 3.72 (32) (020), 3.40 (20) (002, 021), 3.199 (25) (012), 3.000 (26), ( $01\bar 2$ , $1\bar 20$ ), 2.885 (100) (221, $2\bar 11$ , $1\bar 21$ ), 2.691 (21) (222, $2\bar 10$ ), 2.397 (21) ( $02\bar 2$ , $21\bar 1$ , 203, 031), 1.774 (37) (412, $3\bar 21$ ). The type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4420/1.

New Mineral Names

### Dashkovaite* N.V. Chukanov, D.I. Belakovsky, S.V. Malinko, N.I. Organova (2000) Dashkovaite Mg(HCO3)2·2H2O — A new formate mineral. Zapiski Vseross. Mineral. Obshch., 129(6), 49–53 (in Russian, English abs.). Chemical analysis gave C 16.2, H 3.9, Mg 16.4, Mn (by electron microprobe) 0.2, O (by difference) 63.3, sum 100 wt%, corresponding to Mg1.00Mn0.01H5.74C2.00O5.87, ideally Mg(HCO3)2 2H2O. The mineral occurs as white, fibrous aggregates in hydrothermal veinlets, up to 1 mm in width, wherein the fibers are up to 3 mm long and 0.01 mm wide. Soft and porous, H = 1, D calc = 1.74 g/cm3 for Z = 4. Microscopically colorless, biaxial positive, α = 1.465(3), α = 1.486(3), γ = 1.516(3), 2 V calc = 81(5)°, X parallel to the elongation. By analogy with the synthetic analog, indexing of the X-ray powder pattern gave a monoclinic cell, space group P 21/ c , a = 8.64(1), b = 7.15(1), c = 9.38(1) A, α = 98.0(1) °; strongest lines of the pattern (57 mm camera, Fe K α radiation) are 4.90(90,111), 4.64(80,002), 4.30(70,200), 3.68(80,210), and 3.40(100,112). The IR spectrum is similar to that of the synthetic compound. The mineral occurs with shabynite, iowaite, ekaterinite, korshunovskite, halite, hydromagnesite, and serpentine in dolomite marble at the Korshunovskoye boron deposit in the Irkutsk district, Siberia. The new mineral name is for E.R. Dashkova (1744–1810), former Director of the Saint Petersburg Academy of Sciences (1783–1796) and President of the Russian Academy of Sciences. Type material is in the Fersman Mineralogical Museum, Moscow, Russia. J.L.J. ### Fluorannite* Ganfu Shen, Qi Lu, Jinsha Xu (2000) Fluorannite: A new mineral of the mica group from the western suburb of Suzhou City. Acta Petrologica Mineral., 19(4), 355–362 …

A new mineral species rossovskyite, (Fe3+,Ta)(Nb,Ti)O4: crystal chemistry and physical properties

A new mineral rossovskyite named after L.N. Rossovsky was discovered in granite pegmatites of the Bulgut occurrence, Altai Mts., Western Mongolia. Associated minerals are microcline, muscovite, quartz, albite, garnet of the almandine–spessartine series, beryl, apatite, triplite, zircon, pyrite, yttrobetafite-(Y) and schorl. Rossovskyite forms flattened anhedral grains up to 6 × 6 × 2 cm. The color of the mineral is black, and the streak is black as well. The luster is semi-metallic, dull. Mohs hardness is 6. No cleavage or parting is observed. Rossovskyite is brittle, with uneven fracture. The density measured by the hydrostatic weighing method is 6.06 g/cm2, and the density calculated from the empirical formula is 6.302 g/cm3. Rossovskyite is biaxial, and the color in reflection is gray to dark gray. The IR spectrum contains strong band at 567 cm−1 (with shoulders at 500 and 600 cm−1) corresponding to cation–oxygen stretching vibrations and weak bands at 1093 and 1185 cm−1 assigned as overtones. The reflection spectrum in visible range is obtained. According to the Mossbauer spectrum, the ratio Fe2+:Fe3+ is 35.6:64.4. The chemical composition is as follows (electron microprobe, Fe apportioned between FeO and Fe2O3 based on Mossbauer data, wt%): MnO 1.68, FeO 5.92, Fe2O3 14.66, TiO2 7.69, Nb2O5 26.59, Ta2O5 37.51, WO3 5.61, total 99.66. The empirical formula calculated on four O atoms is: \( {\text{Mn}}_{0.06}^{2 + } \)\( {\text{Fe}}_{0.21}^{2 + } \)\( {\text{Fe}}_{0.47}^{3 + } \)Ti0.25Nb0.51Ta0.43W0.06O4. The crystal structure was determined using single-crystal X-ray diffraction data. The new mineral is monoclinic, space group P2/c, a = 4.668(1), b = 5.659(1), c = 5.061(1) A, β = 90.21(1)o; V = 133.70(4) A3, Z = 2. Topologically, the structure of rossovskyite is analogous to that of wolframite-group minerals. The crystal-chemical formula of rossovskyite is [(Fe3+, Fe2+, Mn)0.57Ta0.32Nb0.11][Nb0.40Ti0.25Fe0.18Ta0.11W0.06]O4. The strongest lines of the powder X-ray diffraction pattern [d, A (I, %) (hkl)] are as follows: 3.604 (49) (110), 2.938 (100) (−1−11), 2.534 (23) (002), 2.476 (29) (021), 2.337 (27) (200), 1.718 (26) (−202), 1.698 (31) (−2−21), 1.440 (21) (−311). The type specimen of rossovskyite is deposited in the Mineralogical Museum of the Tomsk State University, Tomsk, 634050 Russia, with the inventory number 20927.

Ferro-pedrizite, NaLi2(Fe2+ 2Al2Li)Si8O22(OH)2, a new amphibole-supergroup mineral from the Sutlug pegmatite, Tyva Republic, Russia

Ferro-pedrizite, a new amphibole-supergroup mineral was discovered in the Sutlug pegmatite occurrence situated in the Targi River Basin, Tyva Republic, Eastern Sibera, Russia. The associated minerals are quartz, albite, microcline, spodumene, cassiterite, beryl, columbite-(Mn), fergusonite-β-(Y), fluorapatite, schorl, trilithionite and fluorite. Ferro-pedrizite forms dark grey-blue to violet-blue acicular and long prismatic crystals up to 2 × 5 × 50 mm and their aggregates. D meas = 3.16(1) g/cm3 (by hydrostatic weighing), 3.13(1) g/cm3 (by flotation in heavy liquids); D calc = 3.135 g/cm3. Ferro-pedrizite is optically biaxial (−), α = 1.614(3), β = 1.638(3), γ = 1.653(3), 2 V meas = 75(5)°, 2 V calc = 76°. The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, the ratio Fe2+:Fe3+ by Mossbauer data, Li by ICP-MS, H2O by gas chromatography of ignition products, F by wet analysis, wt. %): Li2O 4.67, Na2O 2.54, K2O 0.13, MgO 4.48, CaO 0.29, MnO 0.59, FeO 9.06, Al2O3 13.13, Fe2O3 4.60, SiO2 57.59, F 1.15, H2O 1.50, -O = F −0.48, total 99.25. The empirical formula based on 24 anions is: (Na0.60K0.02)∑0.62(Li1.89Na0.07Ca0.04)∑2.00(Fe2+1.03Mg0.90Mn2+0.07Al1.88Fe3+0.47Li0.65)∑5.00[(Si7.79Al0.21)∑8.00O22][(OH)1.36F0.49O0.15)]. The simplified formula is NaLi2(Fe2+2Al2Li)Si8O22(OH)2. Ferro-pedrizite is monoclinic, C 2/ m , a = 9.3716(4), b = 17.649(1), c = 5.2800(6) A, β = 102.22(1)°, V = 853.5(1) A3, Z = 2. The structure has been refined to R obs = 3.9 % (4843 I > 2σ I ). A twinning model was introduced into the refinement through the matrix [−1 0 0/0−1 0/−0.7516 0 1] with the ratio of two twin components of 0.681(3)/0.319(3). The strongest lines of the powder X-ray diffraction pattern [ d , A( I , %) ( hkl )] are: 8.147 (52) (110), 4.420 (22), (040), 3.009 (100) (310), 2.7102 (28) (330), 2.6865 (29) (151), 2.6236 (21) (461). Type material is deposited in the Mineralogical Museum of the Tomsk State University, Tomsk, Russia.

Zvyaginite, NaZnNb2Ti[Si2O7]2O(OH,F)3(H2O)4 + x (x < 1), a new mineral of the epistolite group from the Lovozero Alkaline Pluton, Kola Peninsula, Russia

A new mineral, zvyaginite, a member of the epistolite group, has been found at Mt. Malyi Punkaruaiv, Lovozero Alkaline Complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with ussingite, microcline, aegirine, sphalerite, vigrishinite, and sauconite. Zvyaginite forms rectangular or irregular-shaped lamellae up to 0.1 × 1 × 2 cm in size when flattened [001]. The mineral is translucent to transparent and colorless, pearly-white, yellowish brownish, pale pink, or violet pink. The luster is nacreous on crystal faces and greasy on broken surfaces. Its Mohs’ hardness is 2.5–3. Zvyaginite is brittle. The cleavage parallel to {001} is perfect. Dmeas = 2.88(3), Dcalc = 2.94 g/cm3. The mineral is optically biaxial (−), α = 1.626(5), β = 1.714(3), γ = 1.740(5), 2Vmeas = 45(15)°, 2Vcalc = 55°. The IR spectrum is given. Chemical composition is as follows (wt %; average of five point analyses; H2O was determined using the modified Penfield method): 4.74 Na2O, 0.22 K2O, 0.77 CaO, 1.36 MnO, 0.24 FeO, 9.61 ZnO, 0.19 Al2O3, 29.42 SiO2, 12.33 TiO2, 27.22 Nb2O5, 1.94 F, 12.65 H2O, −0.82 −O = F2, for a total of 99.87. The empirical formula calculated on the basis of Si + Al = 4 is: Na1.24K0.04Ca0.11Mn0.16Fe0.03Zn0.96Nb1.66Ti1.25(Si3.97Al0.03)Σ4O15.07(OH)2.10F0.83(H2O)4.64. The simplified formula is: NaZnNb2Ti[Si2O7]2O(OH,F)3(H2O)4 + x (x < 1), Zvyaginite is triclinic, \(P\bar 1\), a = 8.975(3), b = 8.979(3), c = 12.135(4) A, α = 74.328(9)°, β = 80.651(8)°, γ = 73.959(8)°, V = 900.8(6) A3, Z = 2. The strongest reflections in the X-ray powder pattern (d, A-I[hkl]) are: 11.72–100[001], 5.83–40[002], 5.28–53[−1–11, 112], 4.289–86[200, 021], 3.896–36[−1–12, −201, 003, 022, 113], 2.916–57[310, 132, 004], 2.862–72[130, 312]. The model of the crystal structure was obtained on a single crystal, R = 0.159. Zvyaginite and epistolite are similar in the structure of the NbTiSiO motif, but differ from each other in composition of O layer in HOH block. Zvyaginite is named in honor of Boris B. Zvyagin (1921–2002), Russian crystallographer, crystal chemist and physicist. The type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

Ferroindialite (Fe2+,Mg)2Al4Si5O18, a new beryl-group mineral from the Eifel volcanic region, Germany

A new mineral, ferroindialite, a Fe2+-dominant analog of indialite, has been found in a pyrometamorphosed xenolith of pelitic rock hosted in alkaline basalts. Associated minerals are phlogopite, sanidine, sillimanite, pyroxenes of the enstatite-ferrosilite series, wagnerite, fluorapatite, tridymite, zircon and almandine. Ferroindialite forms brown-purple to gray with a violet-blue tint short prismatic or thick tabular hexagonal crystals up to 1.5 mm in size. The new mineral is brittle, with a Mohs’ hardness of 7. Cleavage is not observed. Dmeas = 2.66(1), Dcalc = 2.667 g/cm3. IR spectrum shows neither H2O nor OH groups. Ferroindialite is anomalously biaxial (−), α = 1.539(2), β = 1.552(2), γ = 1.554(2), 2Vmeas = 30(10)°. The mineral is weakly pleochroic, ranging from colorless on X to pale violet on Z. Dispersion is weak, r < v. The chemical composition (electron microprobe, mean of five point analyses, wt %) is as follows: 0.14 Na2O, 0.46 K2O, 4.95 MgO, 1.13 MnO, 12.66 FeO, 2.64 Fe2O3, 30.45 Al2O3, 47.22 SiO2, total is 99.65. The distribution of total iron content between Fe2+ and Fe3+ was carried out according to structural data. The empirical formula of ferroindialite is: (K0.06Na0.03)(Fe1.122+Mg0.78Mn0.10)Σ2.00(Al3.79Fe0.213+)Σ4.00Si4.98O18. The simplified formula is: (Fe2+,Mg)2Al4Si5O18. The crystal structure has been refined on a single crystal, R = 0.049. Ferroindialite is hexagonal, space group P6/mcc; a = 9.8759(3), c = 9.3102(3) A, V = 786.40(3) A3, Z = 2. The strongest lines in the X-ray powder diffraction pattern [d, A (I, %) (hkl)] are: 8.59 (100) (100), 4.094 (27) (102), 3.390 (35) (112), 3.147 (19) (202), 3.055 (31) (211), 2.657 (12) (212), 1.695 (9) (224). The type specimen of ferroindialite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4400/1.

The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014

Click to increase image sizeClick to decrease image size ACKNOWLEDGMENTSI was deeply honored to be welcomed back for the Second China (Changsha) Mineral and Gem Show and wish to again express my warm appreciation for Mr. Xiao's ambitious vision and hospitality. Dr. John Hou deserves special thanks for making Changsha such a pleasant repeat experience. His work with the volunteers was again nothing short of spectacular, and it was a blast getting to know Zoe, Kendra, Lauren, and Leo from this enthusiastic crew. Dr. Guanghua Liu is also thanked for his careful review of the locality attributions and a delightful dinner. Dr. Rob Lavinsky continues to provide support and advice to the show organizers and the Chinese collecting community in general. I also thank the (reduced) international contingent, especially Bryan Lees, Richard Jackson, Monica Kitt, Gene Meireran, Steve Smale, Andreas Massanek, George Stacey, and Allan Arnold for hospitality and companionship. Finally, my deepest thanks go to Cassie for her local knowledge, excellent translations, and ready smile (good luck on your exams!).The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 20. Cabinet-sized group (20 cm) of emerald crystals from Malipo, Wenshan City, Yunnan Province, China, worked out of matrix.Display full sizeFigure 20. Cabinet-sized group (20 cm) of emerald crystals from Malipo, Wenshan City, Yunnan Province, China, worked out of matrix.The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 21. Purple octahedral fluorites with quartz coating partially removed. Nice to see the physical removal instead of chemical overcleaning with hydrofluoric acid.Display full sizeFigure 21. Purple octahedral fluorites with quartz coating partially removed. Nice to see the physical removal instead of chemical overcleaning with hydrofluoric acid.The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 22. Purple cubic fluorites with prominent growth spirals on each cube face from Weishan, Yunnan Province, China—highly reminiscent of the material from El Filo mine, Mapimi, Durango, Mexico.Display full sizeFigure 22. Purple cubic fluorites with prominent growth spirals on each cube face from Weishan, Yunnan Province, China—highly reminiscent of the material from El Filo mine, Mapimi, Durango, Mexico.The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 23. Radiating group (25 cm) of white nailhead calcites from Nanyang City, Henan Province, China. A number of these were on offer, and this one found a home at the Rice Mineralogical Museum in Portland, Oregon.Display full sizeFigure 23. Radiating group (25 cm) of white nailhead calcites from Nanyang City, Henan Province, China. A number of these were on offer, and this one found a home at the Rice Mineralogical Museum in Portland, Oregon.The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 24. Large plate (35 cm) of new orange-red wulfenites leached out of massive calcite, unfortunately at the price of its luster, from Malan, Xinjiang Province, China.Display full sizeFigure 24. Large plate (35 cm) of new orange-red wulfenites leached out of massive calcite, unfortunately at the price of its luster, from Malan, Xinjiang Province, China.The Second China (Changsha) Mineral and Gem Show, 15–20 May 2014All authorsPeter Megawhttps://doi.org/10.1080/00357529.2014.949169Published online:23 October 2014Figure 25. The Changsha Show has arrived—they had tailgaters on Saturday and Sunday afternoons!Display full sizeFigure 25. The Changsha Show has arrived—they had tailgaters on Saturday and Sunday afternoons!Additional informationNotes on contributorsPeter MegawDr. Peter Megaw, a consulting editor of Rocks & Minerals, is a well-known geologist, mineral collector, author, and longtime exhibits chair for the Tucson Gem and Mineral Show.™

Okruschite, Ca2Mn2+

The new mineral okruschite (IMA No. 2013–047), the arsenate analogue of roscherite, was discovered in a hydrothermal vein cross-cutting rhyolite exposed in the Fuchs quarry, near Sailauf, Spessart Mountains, Bavaria, Germany. Associated minerals are braunite, Mn-bearing calcite and arseniosiderite. Okruschite forms tabular aggregates up to 0.15 × 0.3 × 0.3 mm in size of curved and somewhat misaligned laths. It is white, semitransparent; lustre is vitreous. D meas = 3.33(2), D calc = 3.340 g/cm 3 . Okruschite is optically biaxial (−), α = 1.671(3), β = 1.682(2), γ = 1.687(3), 2 V meas = 65(5)°. The infrared spectrum is given. The chemical composition is (electron microprobe, B and Li by ICP MS, H 2 O by gas chromatography of ignition products, wt. %): Li 2 O 0.04, BeO 7.70, MgO 1.68, CaO 8.28, MnO 16.27, FeO 4.89, Al 2 O 3 0.22, As 2 O 5 51.11, H 2 O 11.0, total 101.19. The empirical formula based on 34 O atoms is: Ca 1.99 (Mn 3.09 Fe 0.92 Mg 0.56 Al 0.06 Li 0.04 ) ∑4.67 Be 4.15 (AsO 4 ) 5.99 (OH) 3.64 · 6.40H 2 O. The simplified formula is Ca 2 Mn 2+ 5 Be 4 (AsO 4 ) 6 (OH) 4 · 6H 2 O. Okruschite is monoclinic, C 2/ c , a = 16.33(4), b = 12.03(3), c = 6.93(1) A, β = 94.84(5)°, V = 1357(4) A 3 , Z = 2. The strongest lines of the powder X-ray diffraction pattern [ d , A ( I , %) ( hkl )] are: 9.68 (39) (110), 4.95 (34) (310), 4.17 (34) (−311), 3.25 (100) (−202, 330), 3.11 (32) (−421), 2.841 (27) (240), 2.711 (26) (600), 1.726 (26) (461, −552, 004). Okruschite is named after Professor Martin Okrusch, from Germany. Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow.

Belakovskiite, Na7(UO2)(SO4)4(SO3OH)(H2O)3, a new uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA

AbstractThe new mineral belakovskiite (IMA2013-075), Na7(UO2)(SO4)4(SO3OH)(H2O)3, was found in the Blue Lizard mine, Red Canyon, White Canyon district, San Juan County, Utah, USA, where it occurs as a secondary alteration phase in association with blödite, ferrinatrite, kröhnkite, meisserite and metavoltine. Crystals of belakovskiite are very pale yellowish-green hair-like fibres up to 2 mm long and usually no more than a few mm in diameter. The fibres are elongated on [100] and slightly flattened on {021}. Crystals are transparent with a vitreous lustre. The mineral has a white streak and a probable Mohs hardness of ∼2. Fibres are flexible and elastic, with brittle failure and irregular fracture. No cleavage was observed. The mineral is readily soluble in cold H2O. The calculated density is 2.953 g cm−3. Optically, belakovskiite is biaxial (+) with α = 1.500(1), β = 1.511(1) and γ = 1.523(1) (measured in white light). The measured 2V is 87.1(6)° and the calculated 2V is 88°. The mineral is non-pleochroic. The partially determined optical orientation is X ≈ a. Electron-microprobe analysis provided Na2O 21.67, UO3 30.48, SO3 40.86, H2O 6.45 (structure), total 99.46 wt.% yielding the empirical formula Na6.83(U1.04O2)(SO4)4(S0.99O3OH)(H2O)3 based on 25 O a.p.f.u. Belakovskiite is triclinic, P, with a = 5.4581(3), b = 11.3288(6), c = 18.4163(13) Å, α = 104.786(7)°, β = 90.092(6)°, γ = 96.767(7)°, V = 1092.76(11) Å3 and Z = 2. The eight strongest X-ray powder diffraction lines are [dobs Å(I)(hkl)]: 8.96(35)(002), 8.46(29)(011), 5.19(100)(01,101,10), 4.66(58)(013,02,0,110), 3.568(37)(120,023,005,03), 3.057(59)(06,15,31), 2.930(27)(multiple) and 1.8320(29)(multiple). The structure, refined to R1 = 5.39% for 3163 Fo &gt; 4σF reflections, contains [(UO2)(SO4)4(H2O)]6− polyhedral clusters connected via an extensive network of Na−O bonds and H bonds involving eight Na sites, three other H2O sites and an SO3OH (hydrosulfate) group. The 3-D framework, thus defined, is unique among known uranyl sulfate structures. The mineral is named for Dmitry Ilych Belakovskiy, a prominent Russian mineralogist and Curator of the Fersman Mineralogical Museum.

Hillesheimite, (K,Ca,□)2(Mg,Fe,Ca,□)2[(Si,Al)13O23(OH)6](OH) · 8H2O, a new phyllosilicate mineral of the Günterblassite group

A new mineral, hillesheimite, has been found in the Graulai basaltic quarry, near the town of Hillesheim, the Eifel Mountains, Rhineland-Palatinate (Rheinland-Pfalz), Germany. It occurs in the late assemblage comprising nepheline, augite, fluorapatite, magnetite, perovskite, priderite, gotzenite, lamprophyllite-group minerals, and akermanite. Colorless flattened crystals of hillesheimite reaching 0.2 × 1 × 1.5 mm in size and aggregates of the crystals occur in miarolitic cavities in alkali basalt. The mineral is brittle, with Mohs’ hard-ness 4. Cleavage is perfect parallel to (010) and distinct on (100) and (001). D calc = 2.174 g/cm3, D meas = 2.16(1) g/cm3. IR spectrum is given. Hillesheimite is biaxial (−), α = 1.496(2), β = 1.498(2), γ = 1.499(2), 2V meas = 80°. The chemical composition (electron microprobe, mean of 4 point analyses, H2O determined from structural data, wt %) is as follows: 0.24 Na2O, 4.15 K2O, 2.14 MgO, 2.90 CaO, 2.20 BaO, 2.41 FeO, 15.54 Al2O3, 52.94 SiO2, 19.14 H2O, total is 101.65. The empirical formula is: K0.96Na0.08Ba0.16Ca0.56Mg0.58Fe 0.37 2+ [Si9.62Al3.32O23(OH)6][(OH)0.82(H2O)0.18] · 8H2O. The crystal structure has been determined from X-ray single-crystal diffraction data, R = 0.1735. Hillesheimite is orthorhombic, space group Pmmn, the unit-cell dimensions are: a = 6.979(11), b = 37.1815(18), c = 6.5296(15) A; V=1694(3) A3, Z = 2. The crystal structure is based on the block [(Si,Al)13O25(OH)4] consisting of three single tetrahedral layers linked via common vertices and is topologically identical to the triple layers in gunterblassite and umbrianite. The strong reflections [d A (I %)] in the X-ray powder diffraction pattern are: 6.857(58), 6.545(100), 6.284(53), 4.787(96), 4.499(59), 3.065(86), 2.958(62), 2.767(62). The mineral was named after its type locality. Type specimens are deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.

Davinciite, Na12K3Ca6Fe 3 2+ Zr3(Si26O73OH)Cl2, a New K,Na-Ordered mineral of the eudialyte group from the Khibiny Alkaline Pluton, Kola Peninsula, Russia

This paper presents a description of a new zirconosilicate of the eudialyte group, which was named davinciite in honor of Leonardo da Vinci (1452–1519), a famous Italian scientist, painter, sculptor and architect. The new mineral has been found in hyperagpaitic pegmatite at the Rasvumchorr Mountain, Khibiny Pluton, Kola Peninsula, as relict inclusions, up to 1–2 mm in size in a rastsvetaevite matrix. It is associated with nepheline, sodalite, potassium feldspar, delhayelite, aegirine, shcherbakovite, villiaumite, nitrite, nacaphite, rasvumite, and djerfisherite. Davinciite is dark lavender and transparent, with a vitreous luster and white streak. The new mineral is brittle, with conchoidal fracture; the Mohs’ hardness is 5. No indications of cleavage or parting were observed. The measured density is 2.82(2) g/cm3 (volumetric method); the calculated density is 2.848 g/cm3. Davinciite is optically uniaxial, positive; ω = 1.603(2), ɛ = 1.605(2). It is nonpleochroic and nonfluorescent in UV light. The new mineral slowly breaks down and gelates in 50% HCl and HNO3. It is trigonal, space group R3m. The unit-cell dimensions are a = 14.2956(2), c = 30.0228(5) A, V=5313.6(2) A3. The strongest reflections in the X-ray powder diffraction pattern [d, A (I, %) (hkl)] are as follows: 2.981(100)(315), 2.860(96)(404), 4.309(66)(205), 3.207(63)(208), 6.415(54)(104), 3.162(43)(217). The chemical composition (electron microprobe, H2O calculated from X-ray diffraction data) is as follows, wt %: 12.69 Na2O, 3.53 K2O, 11.02 CaO, 0.98 SrO, 0.15 BaO, 5.33 FeO, 0.37 MnO, 0.07 Al2O3, 51.20 SiO2, 0.39 TiO2, 11.33 ZrO2, 0.21HfO2, 0.09 Nb2O5, 1.89 Cl, 0.93H2O, -O = Cl2 0.43; total is 99.75. The empirical formula calculated on the basis of Si + Al + Zr + Hf + Ti + Nb = 29 (Z = 3) is (Na1l.75Sr0.29Ba0.03)Σ12.07(K2.28Na0.72)Σ3Ca5.99(Fe2.26Mn0.16)Σ2.42(Zr2.80Ti0.15Hf0.03Nb0.02) Σ3(Si1.96Al0.04)Σ2[Si3O9]2 [Si9O27]2[(OH)1.42O0.58]Σ2[Cl1.62(H2O)0.38]Σ2 · 0.48H2O. The simplified formula is Na12K3Ca6Fe 3 2+ Zr3(Si26O73OH)Cl2. The IR-spectrum is given and the crystal structure is described. The position of davinciite in the crystal chemical taxonomy of the eudialyte group is shown, and its relationships with the other eudialyte-group minerals (acentric eudialyte, andrianovite, and kentbrooksite) are characterized. The type material of davinciite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

Ferrotochilinite, 6FeS · 5Fe(OH)2, a new mineral from the Oktyabr’sky deposit, Noril’sk district, Siberia, Russia

A new mineral, ferrotochilinite, ideally 6FeS · 5Fe(OH)2, was found at the Oktyabr’sky Mine, Oktyabr’skoe Cu-Ni deposit, Noril’sk, Krasnoyarsk krai, Siberia, Russia. It is associated with ferrovalleriite, magnetite and Fe-rich, chlorite-like phyllosilicate in the cavities of pentlandite-mooihoekite-cubanite ore with subordinate magnetite and chalcopyrite. Ferrotochilinite occurs as flattened on [001], prismatic to elongated lamellar crystals up to 0.1 × 0.5 × 3.2 mm, typically split and curved. Aggregates (up to 6.5 mm in size) are fanlike, rosette-like, or chaotic. Ferrotochilinite is dark bronze. The streak is black. The luster is moderately metallic. The Mohs’ hardness is ca. 1; VHN is 13 kg/mm2. Cleavage is {001} perfect, micalike. Individuals are flexible, inelastic. D(calc) = 3.467 g/cm3. In reflected light, ferrotochilinite is gray, with the hue changing from pale beige to bluish; bireflectance is distinct. Anisotropy is distinct, with gray bluish to yellowish beige rotation colors. No internal reflections. Reflectance values [R min-R max, % (λ, nm)] are: 11.6–11.4 (470), 11.2–12.4 (546), 11.1–13.6 (589), 11.0–15.5 (650). The IR spectrum shows the presence of (OH) groups bonded with Fe cations and the absence of H2O molecules. Chemical composition (wt %; electron probe; H content is calculated) is as follows: 0.02 Mg, 61.92 Fe, 0.03 Ni, 0.09 Cu, 19.45 S, 16.3 O, 1.03 H calc; the total is 98.84. The empirical formula calculated on the basis of 6 S atoms is: Mg0.01Fe10.96Ni0.005Cu0.015S6(OH)10.07 = (Fe5.98Cu0.0015Ni0.005)Σ6S6(OH)9.80(Fe 4.89 2+ Mg0.01)Σ4.90(OH)9.80Fe 0.09 3+ (OH)0.27. Ferrotochilinite is monoclinic, space group is C2/m, Cm or C2, the unit-cell dimensions are: a = 5.463(5), b = 15.865(17), c = 10.825(12) A, β = 93.7(1)°, V = 936(3) A3, Z = 2. The strongest reflections in the X-ray powder diffraction pattern (d, A-I[hkl]) are: 10.83-13[001], 5.392-100[002], 3.281-7[023], 2.777-7[150], 2.696-12[004, $$20\bar 1$$ ], 2.524-12[ $$22\bar 1$$ , $$20\bar 2$$ ], 2.152-8[134, 153], 1.837-11[135, $$17\bar 3$$ ]. Ferrotochilinite is a structural analog of tochilinite, with Fe2+ instead of Mg in the hydroxide part. The type specimen is deposited in Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.

Kasatkinite, Ba2Ca8B5Si8O32(OH)3 · 6H2O6, a new mineral from the Bazhenovskoe deposit, the Central Urals, Russia

A new mineral, kasatkinite, Ba2Ca8B5Si8O32(OH)3 · 6H2O, has been found at the Bazhenovskoe chrysotile asbestos deposit, the Central Urals, Russia in the cavities in rhodingite as a member of two assemblages: (l) on prehnite, with pectolite, calcite, and clinochlore; and (2) on grossular, with diopside and pectolite. Kasatkinite occurs as spherulites or bunches up to 3 mm in size, occasionally combined into crusts. Its individuals are acicular to hair-like, typically split, with a polygonal cross section, up to 0.5 mm (rarely, to 6 mm) in length and to 20 μm in thickness. They consist of numerous misoriented needle-shaped subindividuals up to several dozen μm long and no more than 1 μm thick. Kasatkinite individuals are transparent and colorless; its aggregates are snow white. The luster is vitreous or silky. No cleavage was observed; the fracture is uneven or splintery for aggregates. Individuals are flexible and elastic. The Mohs’ hardness is 4–4.5. D meas = 2.95(5), D calc = 2.89 g/cm3. Kasatkinite is optically biaxial (+), α = 1.600(5), β = 1.603(2), γ = 1.626(2), 2V meas = 30(20)°, 2V calc = 40°. The IR spectrum is given. The 11B MAS NMR spectrum shows the presence of BO4 in the absence of BO3 groups. The chemical composition of kasatkinite (wt %; electron microprobe, H2O by gas chromatography) is as follows: 0.23 Na2O, 0.57 K2O, 28.94 CaO, 16.79 BaO, 11.57 B2O3, 0.28 Al2O3, 31.63 SiO2, 0.05 F, 9.05 H2O, −0.02 −O=F2; the total is 99.09. The empirical formula (calculated on the basis of O + F = 41 apfu, taking into account the TGA data) is: Na0.11K0.18Ba1.66Ca7.84B5.05Al0.08Si8.00O31.80(OH)3.06F0.04 · 6.10H2O. Kasatkinite is monoclinic, space group P21/c, P2/c, or Pc; the unit-cell dimensions are a = 5.745(3), b = 7.238(2), c = 20.79 (1) Å, β = 90.82(5)°, V = 864(1) Å3, Z = 1. The strongest reflections (d Å–I[hkl]) in the X-ray powder diffractions pattern are: 5.89–24[012], 3.48–2.1[006], 3.36–24[114]; 3.009–100[\(12\bar 1\), 121, \(10\bar 6\)], 2.925–65[106, \(12\bar 2\), 122], 2.633–33[211, 124], 2.116–29[\(13\bar 3\), 133, 028]. Kasatkinite is named in honor of A.V. Kasatkin (b. 1970), a Russian amateur mineralogist and mineral collector who has found this mineral. Type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

Vigrishinite, Zn2Ti4 − x Si4O14(OH,H2O,□)8, a new mineral from the Lovozero alkaline complex, Kola Peninsula, Russia

A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with species-defining Zn, was found at Mt. Malyi Punkaruaiv, in the Lovozero alkaline complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with microcline, ussingite, aegirine, analcime, gmelinite-Na, and chabazite-Ca. Vigrishinite forms rectangular or irregularly shaped lamellae up to 0.05 × 2 × 3 cm flattened on [001]. They are typically slightly split and show blocky character. The mineral is translucent to transparent and pale pink, yellowish-pinkish or colorless. The luster is vitreous. The Mohs’ hardness is 2.5–3. Vigrishinite is brittle. Cleavage is {001} perfect. Dmeas = 3.03(2), Dcalc = 2.97 g/cm3. The mineral is optically biaxial (−), α = 1.755(5), β = 1.82(1), γ = 1.835(8), 2Vmeas = 45(10)°, 2Vcalc = 50°. IR spectrum is given. The chemical composition (wt %; average of 9 point analyses, H2O is determined by modified Penfield method) is as follows: 0.98 Na2O, 0.30 K2O, 0.56 CaO, 0.05 SrO, 0.44 BaO, 0.36 MgO, 2.09 MnO, 14.39 ZnO, 2.00 Fe2O3, 0.36 Al2O3, 32.29 SiO2, 29.14 TiO2, 2.08 ZrO2, 7.34 Nb2O5, 0.46 F, 9.1 H2O, −0.19 O=F2, total is 101.75. The empirical formula calculated on the basis of Si + Al = 4 is: H7.42(Zn1.30Na0.23Mn0.22Ca0.07Mg0.07K0.05Ba0.02)Σ1.96(Ti2.68Nb0.41Fe0.183+Zr0.12)Σ3.39(Si3.95Al0.05)Σ420.31F0.18. The simplified formula is: Zn2Ti4−xSi4O14(OH,H2O,□)8 (x < 1). Vigrishinite is triclinic, space group P\(\bar 1\), a = 8.743(9), b = 8.698(9), c = 11.581(11)A, α = 91.54(8)°, β = 98.29(8)°, γ = 105.65(8)°, V = 837.2(1.5) A3, Z = 2. The strongest reflections in the X-ray powder pattern (d, A, −I[hkl]) are: 11.7-67[001], 8.27-50[100], 6.94-43[0\(\bar 1\)1, \(\bar 1\)10], 5.73–54[1\(\bar 1\)1, 002], 4.17-65[020, \(\bar 1\)\(\bar 1\)2, 200], and 2.861-100[3\(\bar 1\)0, 2\(\bar 2\)2, 004, 1\(\bar 3\)1]. The crystal structure model was obtained on a single crystal, R = 0.171. Vigrishinite and murmanite are close in the structure of the TiSiO motif, but strongly differ from each other in part of large cations and H-bearing groups. Vigrishinite is named in honor of Viktor G. Grishin (b. 1953), a Russian amateur mineralogist and mineral collector, to pay tribute to his contribution to the mineralogy of the Lovozero Complex. The type specimen is deposited in the Fersman Mineralogical Museum of Russian Academy of Sciences, Moscow.

Osumilite-(Mg): Validation as a mineral species and new data

Osumilite-(Mg), the Mg-dominant analogue of osumilite, has been approved by the CNMNC IMA as a new mineral species. The holotype sample has been found at Bellerberg, Eifel volcanic area, Germany. Fluorophlogopite, sanidine, cordierite, mullite, sillimanite, topaz, pseudobrookite and hematite are associated minerals. Osumilite-(Mg) occurs as short prismatic or thick tabular hexagonal crystals reaching 0.5 × 1 mm in size in the cavities in basaltic volcanic glasses at their contact with thermally metamorphosed xenoliths of pelitic rocks. The mineral is brittle, with Mohs’ hardness 6.5. Cleavage was not observed. Color is blue to brown. Dmeas = 2.59(1), Dcalc = 2.595 g/cm3. No bands corresponding to H2O and OH-groups are in the IR spectrum. Osumilite-(Mg) is uniaxial (+), ω = 1.539(2), ɛ = 1.547(2). The chemical composition (electron microprobe, average of 5 point analyses, wt %) is: 0.08 Na2O, 3.41 K2O, 0.04 CaO, 7.98 MgO, 0.28 MnO, 21.57 Al2O3, 3.59 Fe2O3, 62.33 SiO2, total 99.28. The empirical formula is: (K0.72Na0.03Ca0.01)(Mg1.97Mn0.04)[Al4.21Fe0.453+Si10.32]O30. The simplified formula is: KMg2Al3(Al2Si10)O10. The crystal structure was refined on a single crystal, R = 0.0294. Osumilite-(Mg) is hexagonal, space group P6/mcc; a = 10.0959(1), c = 14.3282(2)A, V = 1264.79(6) A3, Z = 2. The strongest reflections in the X-ray powder diffraction pattern [d, A I %) (hkl)] are: 7.21 (37) (002), 5.064 (85) (110), 4.137 (45) (112), 3.736 (43) (202), 3.234 (100) (211), 2.932 (42) (114), 2.767 (51) (204). A type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 4174/1.

Mariinskite, BeCr2O4, a new mineral, chromium analog of chrysoberyl

A new mineral, mariinskite, BeCr2O4, the chromium analog of chrysoberyl, has been found at the Mariinsky (Malyshevo) deposit, the Ural Emerald Mines, the Central Urals, Russia. The mineral is named after its type locality. It was discovered in chromitite in association with fluorphlogopite, Cr-bearing muscovite, eskolaite, and tourmaline. Mariinskite occurs as anhedral grains ranging from 0.01 to 0.3 mm in size; in some cases it forms pseudohexagonal chrysoberyl-type twins. The mineral is dark-green, with a pale green streak; the Mohs’ hardness is 8.5, microhardness VHN = 1725 kg/mm2. Dmeas = 4.25(2) g/cm3, Dcalc = 4.25 g/cm3. Microscopically, it is emerald-green, pleochroic from emerald-green (γ) to yellow-green (β) and greenish yellow (α). The new mineral is biaxial (+), γ = 2.15(1), β = 2.09(3), and α = 2.05(1), 2Vmeas = 80 ± (10)°, 2Vcalc = 80.5°. In reflected light, it is gray with green reflections; Rmax (589) = 12.9%; Rmin (589) = 12.3%, and there are strong, internal green reflections. The strongest absorption bands in the IR spectrum are as follows (cm−1): 935, 700, 614, 534. Space group Pnma, a = 9.727(3), b = 5.619(1), c = 4.499(1) A, V = 245.9(3) A3, Z = 4. The strongest reflections in the X-ray powder diffraction pattern are as follows (d A, I, hkl): 4.08(40)(101), 3.31(90)(111), 2.629(50)(301), 2.434(50)(220), 2.381(40)(311), 2.139(60)(221), 1.651(100)(222). The average chemical composition of mariinskite (electron microprobe, wt %) is as follows: BeO 16.3, Al2O3 23.89, Cr2O3 58.67, Fe2O3 0.26, V2O3 0.26, TiO2 0.61, total is 99.98. The empirical formula, calculated on the basis of four O atoms is Be1.03(Cr1.22Al0.74Ti0.01Fe0.01V0.01)1.99O4. The compatibility index 1 − (Kp/Kc), 0.019, is excellent. The type specimens are deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, and the Ural Geological Museum, Yekaterinburg, Russia.

Steklite, KAl(SO4)2: A finding at the Tolbachik Volcano, Kamchatka, Russia, validating its status as a mineral species and crystal structure

Steklite KAl(SO4)2 has been found in sublimates of the Yadovitaya (Poisonous) fumarole at the second cinder cone of the northern breach of the Great Fissure Tolbachik Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. Steklite was approved as a valid mineral species by the Commission on New Minerals, Nomenclature, and Mineral Classification of the International Mineralogical Association on June 2, 2011 (IMA no. 2011-041). The name steklite is left for this mineral, as it was named by Chesnokov et al. (1995) for its technogenic analog from a burnt dump of coal mine no. 47 at Kopeisk, the Southern Urals, Russia. It is named after the Russian word steklo, meaning glass, in allusion to the visual similarity of its lamellae to thin glass platelets. At Tolbachik, steklite is associated with alumoklyuchevskite, langbeinite, euchlorine, fedotovite, chalcocyanite, hematite, and lyonsite. It occurs as hexagonal or irregular-shaped lamellar crystals with the major form {001} reaching 30 μm in thickness and 0.2 mm (occasionally up to 1 mm) in width. The crystals are frequently split. They are combined into openwork aggregates or thin crusts up to 1.5 × 2.5 cm in area. Steklite is transparent and colorless, with vitreous luster. The cleavage is perfect, parallel to (001). The mineral is brittle. The Mohs’ hardness is 2.5. D calc is 2.797 g/cm3. Steklite is optically uniaxial, (−), ω = 1.546(2), ɛ = 1.533(3). The chemical composition (wt %, electron-microprobe data) is as follows: 0.09 Na2O, 18.12 K2O, 0.08 CaO, 0.03 MnO, 2.02 Fe2O3, 18.18 Al2O3, 61.80 SO3. The total is 100.37. The empirical formula calculated on the basis of eight O atoms is: (K0.997Na0.008Ca0.004)Σ1.009(Al0.925Fe 0.066 3+ Mg0.003Mn0.001)Σ0.995S2.01O8. Steklite is trigonal, space group P321, a = 4.7281(3), c = 7.9936(5) A, V = 154.76(17)A3, Z =1. The strongest reflections in the X-ray powder diffraction pattern (d, A-I[hkl]) are: 8.02–34[001], 4.085–11[100], 3.649–100[011, 101], 2.861–51[012, 102], 2.660 - 19[003], 2.364–25[110], 2.267–14[111, 111, 103], 1.822–12[022, 202]. In the structure of steklite examined in microtwinned crystal with R = 0.0732, the SO4 tetrahedral anions are shared-corners with distorted AlO6 trigonal prisms to form ∞ 2 [(Al, Fe) (SO4)2]− layers coplanar to (001). The K+ cations are in the interlayer space. The type specimen of steklite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.

Lahnsteinite, Zn4(SO4)(OH)6 · 3H2O, a new mineral from the Friedrichssegen Mine, Germany

A new mineral, lahnsteinite, has been found in the dump of the Friedrichssegen Mine, Bad Ems district, Rhineland-Palatinate (Rheinland-Pfalz), Germany. Lahnsteinite, occurring as colorless tabular crystals in the cavities of goethite, is associated with pyromorphite, hydrozincite, quartz, and native copper. The Mohs’ hardness is 1.5; the cleavage is perfect parallel to (001). D calc = 2.995 g/cm3, D meas = 2.98(2) g/cm3. The IR spectrum is given. The new mineral is optically biaxial, negative, α = 1.568(2), β = 1.612(2), γ = 1.613(2), 2V meas = 18(3)°, 2V calc = 17°. The chemical composition (wt %, electron microprobe data; H2O was determined by gas chromatography of ignition products) is as follows: 3.87 FeO, 1.68 CuO, 57.85 ZnO, 15.83 SO3, 22.3 H2O, total is 101.53. The empirical formula is (Zn3.3Fe0.27Cu0.11)Σ3.91(S0.98O4)(OH)5 · 3H2.10O. The crystal structure has been studied on a single crystal. Lahnsteinite is triclinic, space group P1, a = 8.3125(6), b = 14.545(1), c = 18.504(2) A, α = 89.71(1), β = 90.05(1), γ = 90.13(1)°, V = 2237.2(3) A3, Z = 8. The strong reflections in the X-ray powder diffraction pattern [d, A (I, %)] are: 9.30 (100), 4.175 (18), 3.476 (19), 3.290 (19), 2.723 (57), 2.624 (36), 2.503 (35), 1.574 (23). The mineral has been named after its type locality near the town of Lahnstein. The type specimen of lahnsteinite is deposited in the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, registration number 4252/1.

Aklimaite, Ca4[Si2O5(OH)2](OH)4 · 5H2O, a new natural hydrosilicate from Mount Lakargi, the Northern Caucasus, Russia

A new mineral aklimaite, Ca4[Si2O5(OH)2](OH)4 · 5H2O, has been found near Mount Lakargi, Upper Chegem caldera, Kabardino-Balkaria, the Northern Caucasus, Russia, in the skarnified limestone xenolith in ignimbrite. This hydrothermal mineral occurs in a cavity of altered larnite skarn and is associated with larnite, calcium humite-group members, hydrogarnets, bultfonteinite, afwillite, and ettringite. Aklimaite forms transparent, colorless (or occasionally with pinkish tint) columnar or lath-shaped crystals up 3 × 0.1 × 0.01 mm in size, flattened on {001} and elongated along {010}; they are combined in spherulites. The luster is vitreous; the cleavage parallel to the {001} is perfect. D calc = 2.274 g/cm3. The Mohs’ hardness is 3–4. Aklimaite is optically biaxial, negative, 2V meas > 70°, 2V calc = 78°, α = 1.548(2), β = 1.551(3), γ = 1.553(2). The IR and Raman spectra are given. The chemical composition (wt %, electron microprobe) is as follows: 0.06 Na2O, 0.02 K2O, 45.39 CaO, 0.01 MnO, 0.02 FeO, 24.23 SiO2, 0.04 SO3, 3.22 F, 27.40 H2O(calc.), −1.36 -O=F2; the total is 99.03. The empirical formula calculated on the basis of 2Si apfu with O + OH + F = 16 is as follows: (Ca4.02Na0.01)Σ4.03[Si2.00O5.07(OH)1.93][(OH)3.16F0.84] Σ4.00 · 5H2O. The mineral is monoclinic, space group C2/m, a = 16.907(5), b = 3.6528(8), c = 13.068(4) A, β = 117.25(4)·, V= 717.5(4) A3, Z = 2. Aklimaite is representative of the new structural type, the sorosilicate with disilicate groups [Si2O5(OH)2]. The strongest reflections in the X-ray powder patterns [d, A (hkl)] are: 11.64(100)(001), 2.948(32)(310, 203), 3.073(20) (\(\bar 404\), \(\bar 311\)), 2.320(12)(005, 510), 2.901 (11)(004), 8.30(10)\(\left( {\bar 201} \right)\). The type specimen is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow.