Ferro-pedrizite, NaLi (sub 2) (Fe (super 2+) (sub 2) Al (sub 2) Li)Si (sub 8) O (sub 22) (OH) (sub 2) , a new amphibole-supergroup mineral from the Sutlug Pegmatite, Tyva Republic, Russia
Ferro-pedrizite, NaLi (sub 2) (Fe (super 2+) (sub 2) Al (sub 2) Li)Si (sub 8) O (sub 22) (OH) (sub 2) , a new amphibole-supergroup mineral from the Sutlug Pegmatite, Tyva Republic, Russia
European Journal of Mineralogy (June 2015) 27 (3): 417-426
- amphibole group
- Asia
- chain silicates
- chemical composition
- Commonwealth of Independent States
- crystal chemistry
- crystal form
- crystal structure
- formula
- infrared spectra
- Mossbauer spectra
- new minerals
- optical properties
- refinement
- Russian Federation
- silicates
- spectra
- Tuva Russian Federation
- type specimens
- X-ray diffraction data
- ferro-pedrizite
- Sutlug Pegmatite
Ferro-pedrizite, a new amphibole-supergroup mineral was discovered in the Sutlug pegmatite occurrence situated in the Targi River Basin, Tyva Republic, Eastern Siberia, Russia. The associated minerals are quartz, albite, microcline, spodumene, cassiterite, beryl, columbite-(Mn), fergusonite-beta -(Y), fluorapatite, schorl, trilithionite and fluorite. Ferro-pedrizite forms dark grey-blue to violet-blue acicular and long prismatic crystals up to 2 X 5 X 50 mm and their aggregates. D (sub meas) = 3.16(1) g/cm (super 3) (by hydrostatic weighing), 3.13(1) g/cm (super 3) (by flotation in heavy liquids); D (sub calc) = 3.135 g/cm (super 3) . Ferro-pedrizite is optically biaxial (-), alpha = 1.614(3), beta = 1.638(3), gamma = 1.653(3), 2V (sub meas) = 75(5) degrees , 2V (sub calc) = 76 degrees . The infrared spectrum is given. The chemical composition is (EDS-mode electron microprobe, the ratio Fe (super 2+) :Fe (super 3+) by Mossbauer data, Li by ICP-MS, H (sub 2) O by gas chromatography of ignition products, F by wet analysis, wt. %): Li (sub 2) O 4.67, Na (sub 2) O 2.54, K (sub 2) O 0.13, MgO 4.48, CaO 0.29, MnO 0.59, FeO 9.06, Al (sub 2) O (sub 3) 13.13, Fe (sub 2) O (sub 3) 4.60, SiO (sub 2) 57.59, F 1.15, H (sub 2) O 1.50, -O F -0.48, total 99.25. The empirical formula based on 24 anions is: (Na (sub 0.60) K (sub 0.02) ) (sub Sigma 0.62) (Li (sub 1.89) Na (sub 0.07) Ca (sub 0.04) ) (sub Sigma 2.00) (Fe (super 2+) (sub 1.03) Mg (sub 0.90) Mn (super +) (sub 0.07) Al (sub 1.88) Fe (super 3+) (sub 0.47) Li (sub 0.65) ) (sub Sigma 5.00) [(Si (sub 7.79) Al (sub 0.21) ) (sub Sigma 8.00) O (sub 22) ][(OH ) (sub 1.36) F (sub 0.49) O (sub 0.15) )]. The simplified formula is NaLi (sub 2) (Fe (super 2+) (sub 2) Al (sub 2) Li)Si (sub 8) O (sub 22) (OH) (sub 2) . Ferro-pedrizite is monoclinic, C2/m, a = 9.3716(4), b = 17.649(1), c = 5.2800(6) Aa, beta = 102.22(1) degrees , V = 853.5(1) Aa (super 3) , Z = 2. The structure has been refined to R (sub obs) = 3.9 % (4843 I > 2sigma 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, Aa (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.
