Figure 6. Sample ZB-2: ( a ) Particles deposited onto a copper grid (CM20 instrument), showing Zn-illite (Zn-Ilt), K-deficient hendricksite (Hnk, see text for explanation), fraipontite (Frp), and Fe(Mn)-oxi-hydroxides (Fe,Mn-ox). ( b ) Qualitative EDX spectra of K-deficient hendricksite

Fig. 2. Hendricksite in fine-grained peralkaline phonolite, Oktyabrsky massif. Symbols: Hdr – hendricksite; Ae – aegirine; Ab – albite; Ne – nepheline; Ccn – a mineral of the cancrinite group; Sdl – sodalite; Cpt – catapleiite; Cry – cryolite; Ap – fluorapatite. For other symbols see Fig. 1

Fig. 3. BSE images and elemental maps for hendricksite overgrown on Zn-rich kupletskite phenocryst in fine-grained phonolite. For symbols see Figs 1 and 2 . (online version in colour)

Fig. 7. Variations of Zn vs. major elements (in apfu) for Zn-Mn-bearing micas from phonolites of the Oktyabrsky massif, Ukraine, in comparison with Zn-Mn-rich micas from Franklin Furnace and Sterling Hill, NJ, USA. Open squares – hendricksite from the groundmass of fine-grained phonolite

Figure 12. ( a ) 4Si-M + -3R 2+ diagram, showing the compositional variations of di- and trioctahedral phyllosilicates of the Bongará samples. The top left inset illustrates selected literature data: ideal muscovite (M), hendricksite (H), sauconite (S), beidellite (B), kaolinite (K

Fig. 11. Zn-bearing aluminosilicates composition in the system Zn-K-Al VI , based on apfu calculated. Compositions of muscovite (triangle), hendricksite (diamond), and fraipontite (X) are from Deer et al. (1963) , Evans and Strens (1966) , and Cesàro (1927) , respectively.

Fig. 6. Compositional variations of Zn-Mn-bearing micas from phonolites of the Oktyabrsky massif in comparison with Zn- and Mn-rich micas from Zn-Mn deposits. Open squares – hendricksite, Zn-bearing fluorophlogopite and phlogopite from phonolites, Oktyabrsky massif, Ukraine (original data); solid

Figure 1. Classification plot of Mn reference compounds. Different XANES-derived Mn AOS based on absorption-edge position are shown relative to the first maximum in the first XANES derivative at ~6540 eV (after Marcus et al. 2008 ). Note that masutomilite and hendricksite as well as hausmannite

-shell Al could be Si. In triplite and hendricksite, second-shell Mn may also be Fe. Horizontal lines separate the seven different Mn species groups (see text for further details). (Color online.)

F ig . 15. Zn vs. the remaining octahedral cations for phlogopite (phl), annite (ann) (Zn >0.3 a.p.f.u.), siderophyllite (sid), and muscovite (mus) (Zn >0.05 a.p.f.u.) as well as for hendricksite (hen). Numbers of analyses appear in parentheses. Most data were taken from Frondel and Ito

F ig . 14. Mn vs. the remaining octahedral cations in phlogopite (phl), annite (ann), siderophyllite (sid), polylithionite (pol) (Mn >0.3 a.p.f.u.) and muscovite (mus) (Mn >0.15 a.p.f.u.) as well as for montdorite (mon), norrishite (nor), shirozulite (shi) and hendricksite (hen). Numbers

F igure 4. <M1-O> and <M2-O> relations. Nor = norrishite ( Tyrna and Guggenheim 1991 ); Hnd = hendricksite ( Robert and Gasperin 1985 ); Fkn = ferrokinoshitalite ( Guggenheim and Frimmel 1999 ); Ann = annite ( Hazen and Burnham 1973 ); Shr(star)= shirozulite (the present study

by compositional averages of mica varieties. Uncommon true K micas, other alkali element micas, brittle micas, and some further ideal mica members are listed in the boxes outside of the diagram. The position of the Zn-rich mica hendricksite corresponds to its average composition in nature. In the mica formulae

. The spectrum numbers match the numbers in Table 1 : 15 = bixbyite; 16 = bixbyite (syn); 17 = hausmannite; 18 = manganosite; 19 = feitknechtite (syn); 20 = groutite; 21 = manganite (syn); 22 = braunite; 23 = hendricksite; 24 = masutomilite; 25 = rhodochrosite; 26 = triplite; 27 = Mn(II) acetate tetrahydrate