Fluorine-rich amphibole-group minerals may be more [629073]

Introduction
Fluorine-rich amphibole-group minerals may be more
common than is generally recognized. Significant fluorinecontents in amphiboles are reported since about a century(e.g.Doelter, 1914). An examination of the mineral-chem-
istry of amphiboles based on literature data done byPetersen et al. (1982) revealed a number of amphiboles in
which X
F= F/(F+OH) is higher than 0.50. Since this publi-
cation, nine fluoro-members of the amphibole group have
been accepted by the IMA-CNMMN and published. Three
of them are members of the calcic-amphibole group: fluor-cannilloite (Hawthorne et al. , 1996), fluoro-edenite
(Gianfagna & Oberti, 2001) and fluoropargasite(Lupulescu et al. , 2005).High fluorine content in magnesiohastingsite is rarely
reported. Forty-one magnesiohastingsite and hastingsiteanalyses are reported in Deer et al. (1997) but only five of
them have significant fluorine-contents (X
F> 0.25), and
none of them have X F> 0.50. Gaeta & Freda (2001)
reported strontian fluoro-magnesiohastingsite from AlbanHills (Central Italy) with X
Fup to 0.787. These submilli-
metric fluoro-magnesiohastingsite crystals are poikiliticwith numerous inclusions. Therefore they were not suitablefor crystallographic investigations.
The fluoro-magnesiohastingsite described in this paper
has been approved by the Commission on New Mineral andMineral Names of the International MineralogicalAssociation (#2005-002). The type material is deposited atthe Department of Mineralogy of the LandesmuseumEur. J. Mineral.
2006, 18, 503-508
Fluoro-magnesiohastingsite from Dealul Uroi
(Hunedoara county, Romania): Mineral data and crystal structure
of a new amphibole end-member
HANS-PETER BOJAR 1,* and F RANZ WALTER 2
1Department of Mineralogy, Landesmuseum Joanneum, Raubergasse 10, A-8010 Graz, Austria
2Institute of Earth Sciences, Karl-Franzens-University Graz, Universitätsplatz 2, A-8010 Graz, Austria
Abstract: The new mineral fluoro-magnesiohastingsite, ideally (Na,K,Ca)Ca 2(Mg,Fe 3+,Al,Ti) 5(Si,Al) 8O22F2, a member of the
calcic-amphibole-group, occurs in small cavities of an altered hematite-rich xenolith in the quaternary trachyandesite at Dealu l
Uroi, Hunedoara county, Romania. Associated minerals are: titaniferous hematite, augite, phlogopite, enstatite, feldspar, tridy mite,
titanite, fluorapatite, ilmenite and pseudobrookite. The mineral is reddish-brown to yellowish, with a light reddish-brown stre ak,
and has a perfect {110} cleavage. The tenacity is brittle and the Mohs hardness is 6. Optically the mineral is biaxial (+) and weakly
pleochroic, α= 1.642 (yellow-brown), β= 1.647 (light brown), γ= 1.662 (light brown) at 589 nm 2V (meas. and calc.) is 61°,
dispersion was not observed. The orientation of βis parallel to b. The axial plane is (010) ( γ^c= 26ș). It is monoclinic, C2/m,
with the unit-cell parameters a= 9.871(1) Å, b= 18.006(2) Å, c= 5.314(1) Å, β= 105.37(1)°, V= 910.7(2) Å 3,Z= 2. The calcu-
lated density is 3.18 g/cm 3. The strongest lines in the X-ray powder diffraction pattern ( dobsin Å, ( hkl),I) are: 9.008, (020), 27;
8.421, (110), 61; 3.377, (131), 44; 3.271, (240), 61; 3.124, (310), 100; 2.932, (221), 35; 2.805, (330), 28; 2.700, (151), 54.
The crystal structure of fluoro-magnesiohastingsite was refined to R(F) = 0.054 using reflection intensities collected with
MoKαX-radiation. Refined site-scattering values and considerations of mean bond lengths demonstrated an ordering of Fe 3+at
M2. Electron-microprobe data and the A site-scattering values show significant Ca (0.19 apfu) together with K and Na at the Am
and A2 sites. The site-scattering value and bond-length of O3 to cations indicate that this site is occupied by F , which was in di-
rectly confirmed by infrared spectroscopy. The emp-analyses correspond to the empirical formula: A(Na 0.50K0.22Ca0.17)0.89BCa2.00
C(Mg 4.03Fe3+0.70Al0.13Ti0.13)4.99T(Si5.89Al2.11)8.00O22.00F2.00.
Most companion minerals of fluoro-magnesiohastingsite containing fluorine, like phlogopite, fluorapatite and chondrodite,
have a X F= F/(F+OH) > 0.79. Amphiboles of the hosting trachyandesite are fluoro-members (fluoro-edenite to fluoro-magnesio-
hastingsite) as well but they have a more variable Si/Al-ratio as the xenolith-hosted fluoro-magnesiohastingsites.
Key-words: fluoro-magnesiohastingsite, new mineral, amphibole group, crystal structure, Dealul Uroi, Romania.
0935-1221/06/0018-0503 $ 2.70
© 2006 E. Schweizerbart’ sche Verlagsbuchhandlung. D-70176 Stuttgart DOI: 10.1127/0935-1221/2006/0018-0503*E-mail: hans-peter.bojar@stmk.gv.at

H.-P. Bojar, F. Walter
Joanneum Graz (no. 83854-83855). The name is in accor-
dance with the amphibole nomenclature scheme of the
subcommittee on amphiboles of the IMA-CNMMN (Leakeet al. , 1997).
Occurrence and paragenesis
Fluoro-magnesiohastingsite (Fig. 1) was found in a long
abandoned trachyandesite quarry at Dealul Uroi, about 10km east of Deva, Hunedoara county, Romania (23°02’E,45°52’N). Magmatic rocks of neogene age are widespreadin the Apuseni Mountains, western Romania. Thesemagmatites belong to the calc-alkaline and alkaline seriesand most of these rocks plot in the andesite field. In thisregion the magmatic activity developed mainly between14.7 and 7.4 Ma. After a gap of 6 million years the volcanoDealul Uroi was active at 1.6 Ma, so it is the far youngestmagmatic rock in the Apuseni Mountains. Beside the age,also the higher K
2O content distinguish this volcanic rock
from the other magmatites of the Apuseni Mountains.
Because of the higher K 2O content the Uroi rocks are clas-
sified as trachyandesites (Ro u et al. , 2001, 2004).
Koch (1878) published the first very detailed petrog-
raphy of the rock and mineralogical study of the DealulUroi (including the original description of pseudo-brookite). König et al. (2001) give a brief mineralogical
description of Dealul Uroi. Conspicuous are countless ther-
mally altered xenoliths of sedimentary/low metamorphic
origin. Three major types can be distinguished: quartzites,
limestones and hematite-rich xenoliths. The latter have
commonly a layered texture with Ti-hematite-rich andplagioclase-rich layers. These xenoliths show a highporosity with small cavities hosting augite, fluoro-magne-siohastingsite, fluorine-rich phlogopite, tridymite, feldspar,pseudobrookite and subordinately titanite, fluorapatite,enstatite, ilmenite and fluorite. Fluoro-magnesiohastingsiteforms idiomorphic, long-prismatic crystals up to 3 mm andis often found on green augite, frequently associated with
fluorine-rich phlogopite.
Chemical composition
Microchemical analyses were performed with a JEOL
JSM-6310 electron microprobe, equipped with ED- andWD-spectrometers. The working conditions were 15 kVwith a beam current of 5 nA on aluminium. Minerals andsynthetic phases have been used as standards (F: syntheticfluor-phlogopite; Na: jadeite; Ca, Ti: titanite; Mg: olivine;Al: corundum; Si: kaersutite; K: adularia; Fe: garnet, Cr:chromite, P: apatite) and Phi-Rho-Z as data reduction. Themean element concentration from analyses and the range ofthe values are listed in Table 1. The unit formula was calcu-lated on the basis of O+F = 24. The empirical formulas forfluoro-magnesiohastingsite are (analyses 1 & 2, Table 1):
A(Na 0.50K0.22Ca0.17)0.89BCa2.00C(Mg 4.03Fe3+0.70Al0.13Ti0.13)4.99
T(Si5.89Al2.11)8.00O22.00F2.00
A(Na0.53K0.21Ca0.18)0.92B(Ca1.93Mg0.07)2.00C(Mg4.11Fe3+0.65Al0.10Ti0.14)5.00
T(Si5.86Al2.14)8.00O21.99F2.01
Analysis 1 represents the crystal used for crystallo-
graphic investigations.
Infrared spectroscopy
Fourier-transform infrared spectra were obtained with a
Perkin-Elmer Paragon 500 spectrometer in the far to nearinfrared region (400-4000 cm
-1). Powdered fluoro-magne-
siohastingsite was diluted with KBr and dehydrated at110°C. The measurements were performed with a KBr-disc(13 mm diameter). Absorption bands occur at (w – weak,504
Fig. 1. Fluoro-magnesiohastingsite crystals from Dealul Uroi,
Hunedoara district, Romania, SEM photograph.
Table 1. Electron-microprobe analyses of fluoro-magnesiohast-
ingsite from Dealul Uroi, Hunedoara district, Romania.
oxides Formula based on 24 (O + F)
1 2 Range 1 2
SiO 240.77 41.10 39.12-42.37 Si 5.89 Si 5.86
TiO 21.21 1.30 0.87-1.68 [T]Al 2.11 [T]Al 2.14
Al2O313.11 13.33 12.29-14.20 ΣT 8.00 ΣT 8.00
Fe2O36.44 6.09 5.10-6.99 [C]Al 0.13 [C]Al 0.10
MgO 18.70 19.64 18.03-20.82 Fe 3+0.70 Fe 3+ 0.65
CaO 13.99 13.78 12.89-14.72 Mg 4.03 Mg 4.11 Na
2O 1.79 1.90 1.58-2.36 Ti 0.13 Ti 0.14
K2O 1.17 1.14 1.02-1.33 ΣC 4.99 ΣC 5.00
F 4.39 4.45 3.56-4.83 [B]Ca 2.00 [B]Mg 0.07
-O=F 1.84 1.87 ΣB 2.00 [B]Ca 1.93
Σ 99.73 100.86 [A]Ca 0.17 ΣB 2.00
Na 0.50 [A]Ca 0.18
K 0.22 Na 0.53 ΣA 0.89 K 0.21
F 2.00 ΣA 0.92
F 2.01
1: average analysis of the crystal used for crystal-structure refine-
ments (mean of 35 analyses) and 2: average analysis of 4 othercrystal fragments from the same sample (mean of 16 analyses).

m – medium, s – strong): 1056 (w), 950 (s), 731(w),
691(w), 627(w), 515 (m), 465 (s), 434 (w) and 408 (m) cm –
1. The spectrum (Fig. 2) does not show any absorption
bands in the (OH)-stretching region (3800-3600 cm -1). In
Fig. 2, the (OH)-stretching region is also compared withthat of actinolite from Großer Greiner-mountain, Zillertal,Austria and pargasite from Hunza valley, Afghanistan.
Physical and optical properties
Fluoro-magnesiohastingsite is reddish-brown with a
vitreous lustre. Especially small crystals are transparent.Larger crystals have inclusions of hematite, chondrodite,augite and rarely fluorite. The streak is light reddish-brown.No fluorescence was observed under short- or long-waveultraviolet light. The Mohs hardness is 6 and the tenacity isbrittle. It has the usual perfect {110} cleavage of mono-clinic amphiboles. The calculated density is 3.18 g/cm
3.
The density could not be measured because of the smallgrain size of the homogenous crystals and mineral inclu-sions in the larger ones.
Fluoro-magnesiohastingsite is biaxial (+) and weakly
pleochroic with α= 1.642 (yellow-brown), β= 1.647 (light
brown) and γ= 1.662 (light brown) at 589 nm, 2V(meas.
and calc.) is 61°. The Orientation of βis parallel to b. The
axial plane is (010) ( γ^c= 26ș). Dispersion was not
observed.
X-ray diffraction experiments and structure
refinement
Powder X-ray diffraction data were recorded at 295 K
using a D5000 diffractometer (Bruker AXS, twin-Goebelmirrors, Cu Kα). The indexed powder pattern and refined
unit-cell dimensions are given in Table 2.
A single crystal (0.31 ×0.05 ×0.05 mm) of fluoro-
magnesiohastingsite was mounted on a Bruker Apex CCDdiffractometer using graphite-monochromated Mo KαX-
radiation. Data were collected at 100 K and a total of 4754reflections were measured with –12 ≤h≤12, –22 ≤k≤22
and –6 ≤l≤6 and θ
max= 26.3°. Systematic absences, inten-
sity statistics and the crystal structure refinementconfirmed the space group C2/m. The refined cell parame-
ters from single crystal data are a= 9.858(2) Å, b=
17.975(4) Å, c= 5.297(1) Å,
β= 105.45(3)ș, V= 904.8 Å 3.
Data reduction included background, Lorentz-polarisationcorrection, and an empirical absorption correction(SADABS, Bruker Nonius). Reflections with I< 2σ(I)
were excluded leaving 953 unique data with R(int) = 0.040.
The structure was refined with SHELXL-97 (Sheldrick,1997) using neutral-atom scattering factors and correctionsFluoro-magnesiohastingsite from Dealul Uroi 505
Fig. 2. FTIR spectra of fluoro-magnesiohastingsite from Dealul
Uroi, Hunedoara district, Romania. The insert shows an enlarge-ment of the near-infrared area. The (OH)-stretching bands offluoro-magnesiohastingsite (a) are lacking in comparison withpargasite (b), Hunza-valley, Afghanistan and actinolite (c), GroßerGreiner mountain, Zillertal, Austria.Table 2. X-ray powder diffraction data for fluoro-magnesiohast-ingsite.
h k l d obs dcalc I/I0
0 2 0 9.008 9.003 27
1 1 0 8.421 8.415 61*
-1 1 1 4.920 4.918 8
0 4 0 4.502 4.501 15 2 2 0 4.207 4.207 6*
-1 3 1 3.893 3.892 4
1 3 1 3.377 3.376 44 2 4 0 3.271 3.270 61 3 1 0 3.124 3.125 100 2 2 1 2.932 2.932 35
3 3 0 2.805 2.805 28*
-3 3 1 2.746 2.746 31
1 5 1 2.700 2.701 54 0 6 1 2.590 2.589 25
-2 0 2 2.557 2.556 31
4 0 0 2.3801 2.3796 12
-3 5 1 2.3445 2.3444 26 -4 2 1 2.3339 2.3341 23 -3 1 2 2.2969 2.2968 18 -2 4 2 2.2223 2.2228 4
2 6 1 2.1565 2.1566 25 2 0 2 2.0409 2.0413 10
-4 0 2 2.0323 2.0327 11
3 5 1 2.0114 2.0115 11
-3 7 0 1.9980 1.9981 7 -1 9 0 1.9579 1.9578 7 -5 1 0 1.8933 1.8931 15
5 3 0 1.8144 1.8146 9 4 6 1 1.6458 1.6458 26
-4 8 0 1.6353 1.6352 7
1 11 0 1.6130 1.6132 22
-4 0 3 1.6035 1.6034 3
6 0 0 1.5864 1.5864 10
-6 6 1 1.4413 1.4415 23
din Å, * preferred orientation caused by cleavage, unit-cell param-
eters refined from these data are: a= 9.871(1) Å, b= 18.006(2) Å,
c= 5.314(1) Å, β= 105.37(1)˚, V= 910.7(2) Å 3.

H.-P. Bojar, F. Walter
for anomalous dispersion. The refinement was done with
anisotropic displacement parameters, only the split A-site
was refined isotropically, the extinction factor refined to
zero. All cation sites were refined with variable occupancywith restraints based on the chemical data. According to thechemical analyses the O3 site was refined as being fullyoccupied by fluorine. The refinement converged at R1(F) =
0.054 for 903 F
o> 4σ(Fo) and w R2(F2) = 0.140 with
Goodness-of-Fit = 1.108 for all data. The final difference-Fourier map did not exhibit peaks higher than ± 0.80 e/Å
3.
The highest peak at 0, 0.2342, 1/2may indicate a very low
occupancy of the M4’ site but these coordinates could not
be refined.
Crystal data and experimental details given in Table 3.
Atomic coordinates, equivalent isotropic displacementfactors and refined site-scattering values in epfu (electronsper formula unit) are given in Table 4. Anisotropicdisplacement parameters can be obtained from the authors(or through the E.J.M. Editorial Office – Paris). Selectedinteratomic distances and bond angles are summarized inTable 5.
Site populations
The <T1-O> and <T2-O> distances indicate that [4]Al is
partially ordered at T1. Using the equation (2) in Oberti et
al.(1995a) the Al content in T1 is 1.90 apfu. The calcula-
tion of Al in T2 was done with the modified equation (5) ofOberti et al. (1995a) given in Sokolova et al. (2000):
T(2)Al
= [<T2-O>-<T2-O> c] / 0.02836, and resulted in 0.17 apfu
T(2)Al with <T(2)-O> c= 1.6352. The sum of Al = 2.07 apfu
in T1 and T2 is in good agreement with the empiricalformula (
TAl = 2.11) given above.
The refined site-scattering for M2 and the mean <M2-
O> distance of 2.051 Å indicate that Mg and Fe occupy thissite and nearly all iron of this fluoro-magnesiohastingsite isordered at M2 and trivalent (M2: Mg
1.38Fe3+0.62). The
refined lower site-scattering values for M1 and M3 andtheir similar mean bond-distances indicate an equal occu-pation of Mg+Ti+Al+Fe at these sites. The ordering of atrivalent cation at M2 could also be affected by the identityof the O3 anion, which was reported from the ordering ofAl at M2 in synthetic fluor-pargasite (Oberti et al. , 1995b).
In fluoro-magnesiohastingsite the short M1-O3 and M3-O3 distances (2.042 and 2.054 Å respectively) indicate thepresence of fluorine at O3, also confirmed by the refinedhigh O3 site-scattering (18.3 epfu), the microprobe data506
Table 3. Crystal data and experimental details for fluoro-magnesiohastingsite.
a= 9.858(2) Å, b= 17.975(4) Å, c= 5.297(1) Å, β= 105.45(3)°, V= 904.8 Å 3, C2/m
Frame width, scan time, number of frames 0.3˚, 10 s, 2400
Temperature, detector distance: 100 K, 6 cm
Effective transmission 0.814 – 1.000
R(int) before – after SADABS absorption correction: 0.0493 – 0.0276
Measured reflections, unique reflections – refined parameters 4754, 953 – 107 R1(F) = 0.054 for 903 F
o> 4_( Fo)
wR2(F2) = 0.140 and Goodness-of-Fit = 1.108 for all 953 data
Largest difference-Fourier peaks + 0.80 – 0.75 e/Å 3
Table 4. Refined site-scattering (ss, electrons per formula unit, epfu),
atomic fractional coordinates and equivalent isotropic displacementparameters.
Site ss x y z U eq
O1 0.1074(4) 0.0865(2) 0.2197(7) 0.0069(7)
O2 0.1191(4) 0.1715(2) 0.7318(7) 0.0076(7)
O3 18.30 0.1049(5) 0 0.7130(9) 0.0127(9) O4 0.3660(4) 0.2510(2) 0.7885(7) 0.0086(8)
O5 0.3520(4) 0.1404(2) 0.1145(7) 0.0101(8)
O6 0.3470(4) 0.1167(2) 0.6132(7) 0.0106(8) O7 0.3451(6) 0 0.2807(11) 0.0155(12)
T1 0.2822(2) 0.0852(1) 0.3053(3) 0.0059(4)
T2 0.2914(1) 0.1730(1) 0.8143(3) 0.0056(4) M1 25.84 0 0.0871(1)
1/2 0.0073(5)
M2 32.64 0 0.1754(1) 0 0.0068(4)
M3 12.76 0 0 0 0.0067(7) M4 39.95 0 0.2794(1)
1/2 0.0073(4)
Am 5.10 0.0500(14) 1/2 0.1032(28) 0.024(5)
A2 8.20 0 0.4819(4) 0 0.017(2)
Table 5. Selected interatomic distances (Å) and bond angles (ș) for
fluoro-magnesiohastingsite.
T1-O1 1.661(4) T2-O2 1.637(4)
T1-O5 1.688(4) T2-O4 1.607(4) T1-O6 1.684(4) T2-O5 1.650(4) T1-O7 1.671(3) T2-O6 1.664(4) <T1-O> 1.676 <T2-O> 1.640
M1-O1 x 2 2.041(4) M3-O1 x 4 2.059(3)
M1-O2 x 2 2.103(4) M3-O3 x 2 2.054(4) M1-O3 x 2 2.042(3) <M3-O> 2.057 <M1-O> 2.062
M4-O2 x 2 2.425(4) M2-O1 x 2 2.091(4)
M4-O4 x 2 2.336(4)
M2-O2 x 2 2.072(4) M4-O5 x 2 2.605(4) M2-O4 x 2 1.991(4) M4-O6 x 2 2.569(4) <M2-O> 2.051 <M4-O> 2.484
A2-O5 x 2 2.793(7) Am-O5 x 2 3.037(8)
A2-O6 x 2 2.823(6) Am-O5 x 2 3.201(9) A2-O7 x 2 2.421(6) Am-O6 x 2 2.622(10)
Am-O7 2.445(14)
A2-O3 3.799(6) Am-O7 2.515(14) Am-O3 3.279(14) Am-O7 3.150(16) O5-O6-O5 161.6(2) O5-O7-O5 140.7(3) T1-O5-T2 133.2(2) A2-Am 0.71(1) T1-O6-T2 136.0(2) A2-A2 0.65(1) T1-O7-T1 133.0(4) Am-Am 1.26(3)Ueq=1/3[U22+ 1/sin 2β(U11+U33+ 2U13cosβ)]; expression from
Fischer & Tillmanns (1988).

and from infrared spectroscopy. The M4 site is fully occu-
pied by Ca.
The A cations are distributed at Am and A2 (split site)
and the difference-Fourier map indicates A2 > Am. The
refined site-scattering for Am and A2 equals 13.3 epfu.Calculating the epfu contribution of Na and K from theempirical formula (9.6 epfu Na+K), the residue of 3.7 epfuin Am + A2 was assigned to calcium. The site population
of Ca = 0.19 apfu in A from site-scattering refinement is in
good agreement with the empirical formula (
ACa0.17). The
presence of Ca at the A site was first reported from the
structure refinement of fluor-cannilloite (Hawthorne et al. ,
1996) combined with an excess of Al in the T1 site (> 2.0)and no Al at T2.
For fluoro-magnesiohastingsite the proposed formula
based on refined site-scattering values is:
A(Na 0.51K0.21Ca0.19)BCa2.00M1(Mg 1.77Ti0.09Al0.08Fe2+0.06)
M2(Mg 1.38Fe3+0.62)
M3(Mg 0.88Al0.05Ti0.04Fe2+0.03)T1(Si2.10Al1.90)T2(Si3.83Al0.17) O22F2.00.
Conclusions
The new xenolith-hosted mineral fluoro-magnesiohast-
ingsite is part of the Ca-amphibole group. Si is > 5.5 and <6.5, Mg > Fe, Fe
3+> Al [6], (Na+K) A> 0.5 and Ti < 0.5 apfu,
thus classifying this amphibole as a member of the calcic-amphibole group (Fig. 3). The O3-site is completely occu-pied by fluorine (2 apfu). As the fluorine occupies morethan 50% of the O3-site, the correct name according to theIMA-CNMMN rules (Leake et al. , 1997) is: fluoro-magne-
siohastingsite.
The charge balance Fe
2+/Fe3+recalculation (sum of all
cations exclusive Na and K is 15 (15eNK), i.e.minimum
ferric estimate) according to Schumacher (1997) gives thetotal iron as ferric. Therefore, iron is given in Table 1 asFluoro-magnesiohastingsite from Dealul Uroi 507
Fig 3. Composition space Mg/(Mg+Fe tot) – Si (apfu) of xenolith-
hosted fluoro-magnesiohastingsite and rock forming fluoro-amphi-boles (assuming
BCa > 0.5; A(Na+K) > 0.5; Ti < 0.5) from Dealul
Uroi, Romania. Tie lines and mineral names according to the Ca-amphibole scheme. The squares refer to xenolith-hosted fluoro-magnesiohastingsite crystals (Table 1). Triangles show the chemicalvariation of rock-forming fluoro-amphiboles in the trachyandesite(Table 7).Table 6. Representative electron-microprobe analyses of mineralog-ical phases associated with fluoro-magnesiohastingsite from DealulUroi, Hunedoara district, Romania.
1 2 3 4 5 6
phl ttn apt chd psb hem
SiO 2 43.97 31.34 – 34.88 – –
P2O5 – – 42.03 – – –
TiO 2 3.00 34.19 – – 49.54 3.87
Al2O3 10.83 3.61 – – 1.01 2.54
Cr2O3 – – – – 0.44 0.7 0
FeO 2.45 1.58 – 0.73 – –
Fe2O3 – – – – 44.67 89.71
MnO – – – 0.34 – –
MgO 25.32 – – 58.3 0 5.23 2.16
CaO – 28.32 55.09 – – – Na
2O 0.48 – 0.20 – – –
K2O 9.61 – – – – –
F 7.20 2.52 3.09 11.09 – –
-O = F 3.03 1.06 1.30 4.67 – –
Σ 99.83 100.50 99.11 100.67 100.89 98.98
Si 6.12 1.03 – 1.99 – –
P – – 6.00 – – – Ti 0.31 0.85 – – 1.38 0.08 Al 1.78 0.14 – – 0.04 0.08
Cr – – – – 0.01 0.01
Fe
2+ 0.29 0.04 – 0.04 – –
Fe3+ – – – – 1.24 1.75
Mn – – – 0.02 – – Mg 5.26 – – 4.96 0.29 0.08 Ca – 1.00 9.96 – – – Na 0.13 – 0.07 – – – K 1.71 – – – – – F 3.17 0.26 1.65 2.00 – – F/(F+OH) 0.79 0.26 0.83 1.00 – –
Table 7. Electron-microprobe analyses of rock-forming fluoro-
amphiboles from Dealul Uroi, Hunedoara district, Romania.
oxides mean range
SiO 244.87 41.04 – 47.01 Si 6.41 [B]Mg 0.22
TiO 2 1.87 1.22 – 3.53 [T]Al 1.59 Ca 1.78
Al2O39.48 8.08 – 11.84 ΣT 8.00 ΣB 2.00
FeO 9.41 7.02 – 12.73
MgO 18.23 15.63 – 19.26 [C]Al 0.01 Na 0.61
CaO 11.65 10.50 – 12.26 Fe 3+ 0.36 K 0.21
Na2O 2.21 1.77 – 2.62 Fe 2+ 0.77 ΣA 0.82
K2O 1.14 0.70 – 1.36 [C]Mg 3.66
F 4.23 3.90 – 4.82 Ti 0.20 F 1.93
-O=F 1.78 ΣC 5.00 (OH) 0.07
Σ 100.22 F/(F+OH) 0.97Number of cations on the basis of: 1: 22 O (phlogopite), 2: 5 O
(titanite), 3: 25 O (fluorapatite), 4: 9 O (chondrodite), 5: 5 O (pseu-dobrookite) and 6: 3 O (hematite).
Average of 5 analyses. Minimum estimate of ferric iron (15 eNK)method by Schumacher (1997). Formula based on 24 (O, F , OH)assuming (F+OH) = 2.

H.-P. Bojar, F. Walter
Fe3+which is also supported by the mean bond length of
<M2-O>.
Ca is far above the usual “maximum”-value of 2.0 apfu
observed in amphiboles. Only one member of the Ca-
amphibole group, fluor-cannilloite (Hawthorne et al .,
1996), is in excess to this “limit” with Ca in A > 0.5. Ca-contents higher than 2.0 apfu are also observed in sadana-gaite (Deer et al. , 1997), rarely in pargasite (Hawthorne et
al., 1996) and now in fluoro-magnesiohastingsite.
The major chemical variations in fluoro-magnesiohast-
ingsite are in SiO
2and Al 2O3contents (Table 1, Fig. 3). The
Fe3+in fluoro-magnesiohastingsite reflects strong
oxidising conditions during formation. This observation is
also supported by the abundance of hematite.
A pronounced fluorine enrichment of the late-stage
fluid of magmatic crystallization has to be assumed. Anumber of minerals accompanying fluoro-magnesiohast-ingsite also host high amounts of fluorine. Fluorapatite,phlogopite and chondrodite have a X
F> 0.79 (Table 6) or
are nearly end members, as demonstrated by their X F
values. Even titanite has a X Fof 0.26. Rare fluorite can be
observed as tiny inclusions in fluoro-magnesiohastingsite.
Rock-forming fluoro-amphiboles at Dealul Uroi occur
in fine-grained autoclasts in association with augite,plagioclase, hematite, fluorapatite and rarely fluorite. Incontrast to the fluoro-magnesiohastingsite in xenoliths, theSi-content is higher and more variable (6.06 to 6.67 apfu)and
[4]Al≤2.0. Also the Ca-sum is < 2.0, therefore no Ca
is assumed in A (Table 7). In the Ca-amphibole scheme theanalyses plot in the fluoro-edenite and fluoro-magnesio-hastingsite fields (Fig. 3).
Hawthorne et al. (1996) discussed the substitution
ACa
+[4]Al→ ANa + Si for fluor-cannilloite. The chemical
analyses of all fluoro-amphiboles from Dealul Uroiconfirm this substitution scheme.
Acknowledgements: The authors thank Judith
Baumgartner (Institute of Inorganic Chemistry, Universityof Technology, Graz) for the single crystal data acquisition.The authors would to thank U. Kolitsch, an anonymousreviewer and A.-V . Bojar for helpful comments and textrevisions.
References
Deer, W .A., Howie, R.A., Zussman, J. (1997): Rock-Forming
Minerals, V olume 2B, second edition: Double-chain silicates.The Geological Society, London, 764 p.
Doelter, C. (1914): Handbuch der Mineralchemie: Band II, Erste
Hälfte. Silicate. Verlag Theodor Steinkopff, Dresden undLeipzig, 848 p.
Fischer, R.X. & Tillmanns, E. (1988): The equivalent isotropic
displacement factor. Acta Cryst. ,C44, 775-776.
Gaeta, M. & Freda, C. (2001): Strontian fluoro-magnesiohast-
ingsite in Alban Hills lavas (Central Italy): constraints on crys-tallization conditions. Min. Mag. ,65, 787-795.Gianfagna, A. & Oberti, R. (2001): Fluoro-edenite from
Biancavilla (Catania, Sicily, Italy): crystal chemistry of a newamphibole end-member. Am. Mineral. ,86, 1489-1493.
Hawthorne, F .C., Oberti, R., Ungaretti, L., Grice, J.D. (1996): A
new hyper-calcic amphibole with Ca at the A site: Fluor-cannilloite from Pargas, Finland. Am. Mineral. ,81, 995-
1002.
Koch, A. (1878): XXII. Neue Minerale aus dem Andesit des
Aranyer Berges in Siebenbürgen. Tschermaks Mineral.
Petrogr. Mitt. ,1 Neue-Folge , 331-361.
König, U., Benea, M., Göske, J., Pöllmann, H. (2001): Der Berg
Magura Uroiului in Rumänien – Locus Typicus desPseudobrookits. Der Aufschluss ,53, 271-281.
Leake, B.E., Woolley, A.R., Arps, C.E.S., Birch, W .D., Gilbert,
M.C., Grice, J.D., Hawthorne, F .C., Kato, A., Kisch, H.J.,Krivovichec, V .G., Linthout, K., Laird, J., Mandarino, J.A.,Maresch, W .V ., Nickel, E.H., Rock, N.M.S., Schumacher,J.C., Smith, D.C., Stephenson, N.C.N., Ungaretti, L.,Whittacker, E.J.W ., Y ouzhi, G. (1997): Nomenclature ofamphiboles: Report of the Subcommittee of the InternationalMineralogical Association, Commission on New Minerals
and Mineral Names. Can. Mineral. ,35, 219-246.
Lupulescu, M.V ., Rakovan, J., Robinson, G.W ., Hughes, J.M.
(2005): Fluoropargasite, a new member of the calcic amphi-boles from Edenville, Orange County, New Y ork. Can.
Mineral. ,43, 1423-1428.
Oberti, R., Ungaretti, L., Cannillo, E., Hawthorne, F .C., Memmi,
I. (1995a): Temperature-dependent Al order-disorder in thetetrahedral double chain of C2/mamphiboles. Eur. J.
Mineral. ,7, 1049-1063.
Oberti, R., Sardone, N., Hawthorne, F .C., Raudsepp, M.,
Turnock, A.C. (1995b): Synthesis and crystal structurerefinement of synthetic fluor-pargasite. Can. Mineral. ,33,
25-31.
Petersen, E.U., Essene, E.J., Peacor, D.R. (1982): Fluorine end-
member micas and amphiboles. Am. Mineral. ,67, 538-544.
Ro u, E., Szakácz, A., Downes, H., Seghedi, I., Pécskay, Z.,
Panaiotu, C. (2001): The origin of neogene calc-alkaline andalkaline magmas in the Apuseni mountains, Romania: Theadakite connection. Romanian Journal of Mineral Deposits ,
79, suppl. 2, field guide book, 3-23.
Ro u, E., Seghedi, I., Downes, H., Alderton, D.H.M., Szakácz,
A., Pécskay, Z., Panaiotu, C., Panaiotu, C.E., Nedelcu, L.(2004): Extension-related Miocene calc-alkaline magmatismin the Apuseni Mountains, Romania: Origin of magmas.Schweiz. Mineral. Petrogr. Mitt. ,84, 153-172.
Schumacher, J.C. (1997): Appendix 2: The estimation of the
proportion of ferric iron in the electron-microprobe analysisof amphiboles. Can. Mineral .,35, 238-246.
Sheldrick, G.M. (1997): SHELXL-97 program for crystal struc-
ture refinement. University of Göttingen, Germany.
Sokolova, E.V ., Hawthorne, F .C., Kabalov, Y .K., Schneider, J.,
McCammon, C. (2000): The crystal chemistry of potassic-ferrisadanagaite. Can. Mineral .,38, 669-674.
Received 19 January 2006
Modified version received 10 February 2006Accepted 14 March 2006508