On an unnamed Mg-Mn-Sb oxyborate from theblatterite locality of the Kitteln mine, Nordmark,Filipstad, Vilrm land, Sweden
Gunnar Raade & Harald Folvik
lntroduction
Blatterite was described as a new mineral species from the Kitteln mine (Kittelgruvan) at
Nordmark, north of Filipstad, Sweden, by Raade et al. (1988). lt is an orthorhombic Mg-MnSb oxyborate, differing from related minerals of the orthopinakiolite group by its large unit cellwith a = 37 .7 A. lt was shown by an HRTEM investigation (Olsen & Raade 1987 , Raade et al.
1988) that blatterite has the structure type 8Et where the numbers equal the number ofoctahedral layers between a twin plane f.

Cooper& Hawthorne (1998) solved and refined the blatterite structure in space group Pnnm

to an R index of 0.043 and established the refined formula
Sbs*g(Mn3t,Fe3';n1Mn2.,Mg1ru1BOs)roOgz, based on materialfrom the Lingban deposit.

The blatterite-bearing material in the Kitteln mine has evidently been dumped there from anearby mine (Fig. 1). lt was suggested by Raade et al. (1988) that the source might havebeen the Brattfors mine (Brattforsgruvan). However, the closely situated Moss mine(Mossgruvan) is perhaps more likely, from which Bovin et al. (1986,1996) have described ablatterite-like mineral (see below).

,/trP j*",##u,,,!

:r-a.

*-:QFigure 1. The Kitteln mine.
Photo by G. Raade 19. June 201049

Already at the time when blatterite was described, it was clear that a different oxyborate
mineral existed in the material from the Kitteln mine. Blatterite from Kitteln is embedded incalcite or manganosite and forms very characteristic crystals in the form of {110} prisms thatare striated along the length and have a flat, diamond-shaped cross-section (Fig. 2). Crystals
up to 5 mm long and 1 mm wide have been reported. They often have dull surfaces. The
other mineral is present as much smaller, shiny, prismatic crystals which look well-formed
under the binocular microscope but are in fact composed of two or more individuals (Fig. 3).
The two oxyborate minerals do not occur together.
The unknown mineral is black with submetallic lustre and occurs in calcite. A small specimen
was treated with weak hydrochloric acid, and the extracted crystals were hand-picked undera binocular microscope. We had great hopes that these nice crystals might turn out to be anew species. Mark Cooper of the University of Manitoba has examined a large number of the
supposedly individual crystals with a single-crystal diffractometer (personal communication
August 2010). Unfortunately, the crystals are not single prisms but complexly intergrownpolycrystals (Fig. 3). Only one very small crystal gave a unit cell similar to an Sb-bearingpinakiolite from Lingban (a =21.8 A) described by Hansen et al. (1988) and Norrestam &Hansen (1990). For some crystals, a unit-cell repeat of 37A was observed, which is equal tothat of blatterite, but all spots did not fit a single simple cell. We are reporting here on thework done so far and especially on the chemical composition of the mineral.

''7,a*.

w

Figure 2. BSE image of a
striated blatterite crystal fromKitteln. A small cross section isvisible below the prismatic crystal.

Figure 3. BSE image of an
extremely complex aggregate of
the unknown oxyborate fromKitteln, displaying five intergrown
BSEz 28-Fab-13

NHYhlD15. 1m L5.,;kv x4?0t00x50crystals.

Chemical data
The chemical composition was determined with a Cameca SX100 electron microprobe(EMP) in wavelength{ispersive mode at 15 kV acceleration voltage, 15 nA beam current
and with a beam diameter of 1 pm. The probe standards are reported in Table 1. The peaksof the major elements Mg, Mn and Sb were counted for 10 s, and the counting time for theminor elements Fe and Al was 20 s. Ca and Ti were sought but not detected.

The mean result of 17 individual EMP analyses on three grains is presented in Table 1. Twoof the grains are irregular whereas a longitudinal section of a prismatic crystal consists of twoparts in parallel growth, possibly a twin. Most importantly, the mineral did not show any
chemical zonation, and the ranges and standard deviations of the analytical results are quitesmall.
The two irregular grains have inclusions of a Mg-Mn silicate with a ratio of (Mg+Mn):Si close
to 9:4, corresponding to sonolite, Mns(SiO+)+(OH)r, except that the mineral has Mg > Mn andthe F content is not known. lt might well be a new species, the Mg analogue of sonolite.
Alleghanyite, sonolite and manganhumite have previously been identified in the blatteritebearing specimens by X-ray powder diffraction and EMP analyses, and they all have Mn >Mg. lt should be noted that the unknown oxyborate has an appreciably higher Mg content
than blatterite, about 24 versus 12 wt% MgO. Thus the blatterite-bearing assemblage ispoorer in Mg compared to the assemblage of the unknown oxyborate.

A black, porous Mn oxide associated with the unknown oxyborate turned out to be nearly Xray amorphous, but the strongest reflection of hausmannite is probably present. Bovin et al.
(1996) reported their blatterite-related mineral to be associated with hausmannite and calcite.
This is in contrast to blatterite from Kitteln which occurs together with manganosite (Raade etal. 1988). Any associated minerals of blatterite from Lingban are not reported.

Table 1. Electron-microprobe analytical data of an unknown oxyborate from Kitteln

Constituent

Mgo

wt%
24.11

BzOs*"AlzOe
Mn2O3***
FezOs
SbzOs

29.85
15.26
0.27
11.49
0.45
18.15

Total

99.58

MnO

StandardLine

Range

St. dev

22.79-25.06

Mgo

39.0441.64.

0.66
0.89*

Pyrophanite

Mg-Kcr
Mn-Kcr

0.24-O.31

0.02

AlzOa

Al-Kcr

0.36-0.59
17.31-18.55

0.06
0 32

Fe metal

Fe-KcrSbzSa

Sb-Lct* Raw data with total Mn as MnO (mean 40-17 vrrt% MnO)** Calculated to give B:O = 1:5 (i.e. B =16 apfu)*"" Calculated such that the sum of cations (except B) equals 47 apfu.

5lTentatively based on a blatterite cell with 80 O atoms, the empirical formula is
Sb5*+.ro(Mn3* s : r F€3*s 21A16 1e );5 71(Mg 21.6 Mn2t1s.36 )r37 1s(BO3)r6O:z.The simplified formula hasreasonable subscripts: Sbs-4(Mn3.,Fe3.)6(Mg,Mn'z-)37(BOg)roOaz. This can be compared tothe composition of blatterite from L6ngban (Cooper & Hawthorne 1998):
Sbs.3(Mn3-,Fe3')e(Mn'z-,Mg)35(BO:)roorz. The unknown mineral is higher in Sb, has a lower
content of trivalent cations and. most importantly, Mg , Mn'*.

Sb-bearing oxyborates from LAngban{ype deposits in Sweden have been described on
several occasions. ln order to make a comparison with these minerals, the empirical formulaof the Kitteln mineral is divided by 16 and rearranged, with di- and trivalent Mn combined:
Mg1 36Mn 1.2eFee orAlo.or Sbo zo(BOa)Oz (with rounding errors).

- An unnamed oxyborate from an unspecified locality at Nordmark was described by Dunnet al. (1983): (Mgr.rsMno sr )(Mn3*6 73Sb3t615Fe3*o.1rAlo.or XBOg)Oz (Sb should bepentavalent).This composition does not match well with our mineral.
- Sb-rich pinakiolite (space group C2lm) lrom L6ngban (Norrestam & Hansen 1990) has the
structurally refined composition Mgr eo Mno.sr Sbo.rgOzBOg, which also does not correspond toour mineral, but see the discussion below.
-', The blatterite-like mineral from lVossgruvan (Bovin et al. 1996) is much closer,Mgl.33Mn 1.aaFe6.osSbo rzOzBOg, especially with regard to the Mg content.

New single-crystal data
Additional material of the unknown Kitteln mineral was investigated by Mark Cooper in March2013 (personal communication). On a tiny, twinned crystal it was possible to establish amonoclinic cell with a = 21.866, b = 6-212, c = 5.382 A, B = g+.ge', which agrees well with
Sb+ich pinakiolite from L6ngban (Hansen et al. 1988, Norrestam & Hansen 1990). However,it was not possible to come up with a meaningful structure result.

Discussion and conclusion
Bovin et al. (1996) described the structure of a mineral from Mossgruvan, which they calledboth "blatterite" and "a blatterite mineral", based on a combined single-crystal X-ray andelectron microsmpy study. The structural model, deduced from HRTEM images, was refined
to an R value of 0.056. This mineral, with space group Pnnm and a = 37.384 A, can beconsidered as an unnamed Mg analogue of blatterite. Since a structural model wasproposed, it could have been defined as a new species. Our unnamed mineral, which is Mgrich compared to blatterite and is probably also from Mossgruvan, has turned out to berelated to Sb-rich pinakiolite from LSngban.
The Sb-rich pinakiolite was first described as a new structural variety, although it was notedthat it probably fulfilled the requirements of being considered as a new species (Hansen et al.
1988). A struclural solution and refinement to R = 0.047 was achieved by Norrestam &Hansen (1990). Three chemical formulae have been presented for this mineral. One is basedon a combined EMPMDS and ICP investigation (Hansen et al. 1988), and the two others arederived from single-crystal X-ray data (quoted above) and the result of SEM/EDS analysis(Norrestam & Hansen 1990). Comparing the chemical data of Hansen et al. (1988) withthose of the Kitteln mineral reveals an almost identical Sb content but different Mg/Mn ratios(wt%; data for the Kitteln mineral in parentheses): MgO 32.02 (24.1 1 ), total Mn as lvlnO
31.60 (40.17), SbzOs 18.09 (18.15), AlrO3 0.22(O.27), Fe2O3 0.06 (0.45).

52

The fact that some crystals of the Kitteln mineral have cell parameters close to those of Sbrich pinakiolite from Ldngban means thal they are structurally related but they are notnecessarily the same species. This depends on the specific distribution of elements among
the various structure sites. lt is an important factor that the Lengban mineral is quite different
in appearance. lt has a tabular, micaceous habit and is light olive-green to yellowish brownand bronze-like (Hansen et al. 1988).

Both studies of Sb+ich pinakiolite from LAngban report some structural disorder. For theKitteln crystals, it can be concluded that they have much more severe defects that have
prevented a structural solution, and they may be intergrowths of several structure types, ashas been shown previously for other oxyborates by HRTEM (Bovin & O'Keffee 1981, Bovinet al. 't 981 ).

Acknowledgements
Muriel Erambert gave valuable assistance with the EMP analyses, which were made on apolished mount prepared by Alf Olav Larsen.

References
BOVIN, J.-O. & O'KEEFFE, M. (1981 ): Electron microscopy of oxyborates. ll. lntergrowth andstructural defects in synthetic crystals. Acta Crystallographica 437 , 35-42.
BOVIN, J.-O., O'KEEFFE, M. & O'KEEFE, M.A. (1981): Electron microsmpy of oxyborates. l.
Defect structures in the minerals pinakiolite, ludwigite, orthopinakiolite and tak6uchiite. Acfa
Cry sta l l og ra ph i ca 437, 28-35.
BOVTN, J.-O., BARRY, J., THOMASSON, R., NORRESTAM, R. & FALTH, L. (1986): Crystar
structure images of a new mineral, (Mg,Mn,Sb,Fe)r.gtBOs. Proceedings Xlth lnternational
Congress on Electron Microscopy, Kyoto 1986, 1697-1698.

BOV|N, J.-O., CARLSSON, A., SJoVALL, R. & THOMASSON, R. (1996): The crystat
structure of a blatterite mineral, Mg r :aMn 1.aaF€s s5Sb6 17028O3, a combined single crystal Xray and HREM study. Zeitschift f0r Kristallographie 21'l, 440448.

COOPER, M.A. & HAWTHORNE, F.C. (1998): The crystal structure of blatterite,

Sb5.3(Mn3',Fe3*)s(Mn'z-, Mg)3s(Bo:)roO:2, and structural hierarchy in Mn3*-bearing zigzag

borates. The Canadian Mineralogist 36, 1171-1193.
DUNN, P.J., PEACOR, D.R., SIMMONS, W.B. & NEWBURY, D. (1983): Fredrikssonite, a
new member of the pinakiolite group, from LSngban, Sweden. Geologiska F6reningens i
Stockholm Fdrhandlingar 1O5, 335-340 [Printed 1984]HANSEN, S., HALENIUS, U. & LINDQVIST, B. (1988): Antimony-rich pinakiolite fromL6ngban, Sweden: a new structural variety. Neues Jahrbuch f r Alineralogie Monatshefte,23',t-239.

NORRESTAM, R. & HANSEN, S. (1990): Structural investigation of an antimony-richpinakiolite, Mg 1 e6Mns elSbs rsOzBOs, from L6ngban, Sweden. Zeitschrift f r Kistallographie
19'1,105-1 16.

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OLSEN, A. & RAADE, G. (1987): Crystal structure determination of blatterite using analyticalelectron microscopy. Acta Crystallographica M3 (Abstract '14.4-10).
RAADE, G., MLADECK, M.H., DlN, V.K., CRIDDLE, A.J. & STANLEY, C.J. (1988): Blatterite,a new Sb-bearing Mn2*-Mn3. member of the pinakiolite group, from Nordmark, Sweden.
Neues Jahrbuch

f r Mineralogie Monatshefte, '121-136.

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