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Kyanoxalite, a new member of the cancrinite group, has been identified in hydrothermally altered hyperalkaline rocks and pegmatites of the Lovozero alkaline pluton, Kola Peninsula, Russia. It was found at Mount Karnasurt (holotype) in association with nepheline, aegirine, sodalite, nosean, albite, lomonosovite, murmanite, fluorapatite, loparite, and natrolite and at Mt. Alluaiv. Kyanoxalite is transparent, ranging in color from bright light blue, greenish light blue and grayish light blue to colorless. The new mineral is brittle, with a perfect cleavage parallel to (100). Mohs hardness is 5-5.5. The measured and calculated densitiesare 2.30(1) and 2.327 g/cm 3 , respectively. Kyanoxalite is uniaxial, negative, ω = 1.794(1), ε = 1.491(1). It is ple ochroic from colorless along E to light blue along O. The IR spectrum indicates the presence of oxalate anions C 2 and water molecules in the absence of C Oxalate ions are confirmed by anion chromatography. The chemical composition (electron microprobe; water was determined by a modified Penfield method and carbon was determined by selective sorption from annealing products) is as follows, wt %: 19.) 0.13 (PO 4 ) 0.09 (OH) 0.01 ] Σ0.68 ⋅ 4.74H 2 O. The idealized formula is Na 7 (Al 5-6 Si 6-7 O 24 )(C 2 O 4 ) 0.5-1 ⋅ 5H 2 O. Kyanoxalite is hexagonal, the space group is P6 3 , a = 12.744(8), c = 5.213(6) Å. The strongest reflections in the X ray powder diffraction pattern are as follows, [d, [A] (I, %)(hkl). According to the X ray single crystal study (R = 0.033), two independent C 2 O 4 groups statistically occupy the sites on the axis 6 3 . The new mineral is the first natural silicate with an additional organic anion and is the most hydrated member of the cancrinite group. Its name reflects the color (κεανος is light blue in Greek) and the species forming role of oxalate anions. The holotype is deposited at the Fersman Mineralogical Museum of the Russian Academy of Sci ences, Moscow, registration no. 3735/1.

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New minerals, shlykovite and cryptophyllite, hydrous Ca and K phyllosilicates, have been identi fied in hyperalkaline pegmatite at Mount Rasvumchorr, Khibiny alkaline pluton, Kola Peninsula, Russia. They are the products of low temperature hydrothermal activity and are associated with aegirine, potassium feldspar, nepheline, lamprophyllite, eudialyte, lomonosovite, lovozerite, tisinalite, shcherbakovite, shafra novskite, ershovite, and megacyclite. Shlykovite occurs as lamellae up to 0.02 × 0.02 × 0.5 mm in size or fibers up to 0.5 mm in length usually combined in aggregates up to 3 mm in size, crusts, and parallel columnar vein lets. Cryptophyllite occurs as lamellae up to 0.02 × 0.1 × 0.2 mm in size intergrown with shlykovite being ori ented parallel to {001} or chaotically arranged. Separate crystals of the new minerals are transparent and col orless; the aggregates are beige, brownish, light cream, and pale yellowish grayish. The cleavage is parallel to (001) perfect. The Mohs hardness of shlykovite is 2.5-3. The calculated densities of shlykovite and crypto phyllite are 2.444 and 2.185 g/cm 3 , respectively. Both minerals are biaxial; shlykovite: 2V meas = -60(20)°; cryptophyllite: 2V meas > 70°. The refractive indices are: shlykovite: α = 1.500(3), β = 1.509(2), γ = 1.515(2); cryptophyllite: α = 1.520(2), β = 1.523(2), γ = 1.527 (2). The chemical composition of shlykovite determined by an electron microprobe (H 2 O determined from total deficiency) is as follows, wt %: 0.68 Na 2 O, 11.03 K 2 O, 13.70 CaO, 59.86 SiO 2 , 14.73 H 2 O; the total is 100.00. The empirical formula calculated on the basis of 13 O atoms (OH/H 2 O calculated from the charge balance) is (K 0.96 Na 0.09 ) Σ1.05 Ca 1.00 Si 4.07 O 9.32 (OH) 0.68 ⋅ 3H 2 O. The idealized formula is KCa[Si 4 O 9 (OH)] ⋅ 3H 2 O. The chemical composition of cryptophyllite deter mined by an electron microprobe (H 2 O determined from the total deficiency) is as follows, wt %: 1.12 Na 2 O, 17.73 K 2 O, 11.59 CaO, 0.08 Al 2 O 3 , 50.24 SiO 2 , 19.24 H 2 O, the total is 100.00. The empirical formula calcu lated on the basis of (Si,Al) 4 (O,OH) 10 (OH/H 2 O calculated from the charge balance) is (K 1.80 Na 0.17 ) Σ1.97 Ca 0.99 Al 0.01 Si 3.99 O 9.94 (OH) 0.06 ⋅ 5.07H 2 O. The idealized formula is K 2 Ca[Si 4 O 10 ] ⋅ 5H 2 O.The crystal structures of both minerals were solved on single crystals using synchrotron radiation. Shlykovite is monoclinic; the space group is P2 1 /n; a = 6.4897(4), b = 6.9969(5), c = 26.714(2) Å, β = 94.597(8)°, V = 1209.12(15) Å 3 , Z = 4. Cryptophyllite is monoclinic; the space group is P2 1 /n; a = 6.4934(14), b = 6.9919(5), c = 32.087(3) Å, β = 94.680(12)°, V= 1451.9(4) Å, Z = 4. The strongest lines of the X ray powder patterns (d, Å-I, [hkl] are: shlykovite 13.33-100[002], 6.67-76[004], 6.47-55[100], 3.469-45[021], 3.068-57[ 21], 3.042-45[121], 2.945-62[ 23], 2.912-90[025, 12, 211]; cryptophyllite 16.01-100[002], 7.98-24[004], 6.24-48[101], 3.228-22[ 09], 3.197-27[0.0.10], 2.995-47[122], 2.903-84[123, 204, 24, 211], 2.623-20[028, 08, ...

Dellaite crystals of close to end-member composition, Ca6(Si2O7)(SiO4)(OH)2, and with ∼1.5 wt.% Cl. yielding Ca6(Si2O7)(SiO4)(OH)1.75Cl0.25 have been found in skarns within the gabbroid rocks of the Birkhin complex (Eastern Siberia, Russia). The greatest Cl content analysed in a dellaite domain in this skarn is 5.2 wt.% Cl corresponding to 0.8 Cl p.f.u. Dellaite occurs in altered merwmite-larnite-bredigite-gehlenite skarns and also in calcio-olivine skarns with residual larnite. The crystal structures of Cl-free and Cl-bearing (∼1.5 wt.% Cl) dellaite have been refined, including hydrogen positions, from single-crystal X-ray data to R1 = 3.7 and 3.8%, respectively. In addition, both dellaite varieties were studied by Raman spectroscopy indicating stronger hydrogen bonds for the Cl-bearing sample, which agrees with the structural data. Cl is strongly selective and enriches at one (O6) of the two OH positions allowing for the formation of a stronger hydrogen bond O8—H8…C16 compared to O8—H8…O6. Raman spectra of the domain with ∼0.8 Cl p.f.u. confirm the general enhancement of a low-frequency band in the OH range suggesting the dominance of the O—H…Cl hydrogen bond systems.Dellaite and killalaite, Ca3.2(H0.6Si2O7)(OH), have related modular structures, differentiated only by the Si2O7 units in killalaite and alternating Si2O7 and SiO4 units in dellaite. The similarity in cell dimensions and chemical composition suggests that trabzonite, Ca4Si3Oi0-2H2O, with Si3Oi0 trimers also belongs to the same family of structures.