1
Revision 11
Oxy-schorl, Na(Fe2+
2Al)Al6Si6O18(BO3)3(OH)3O, a new mineral from Zlatá Idka, Slovak2
Republic and Přibyslavice, Czech Republic3
4
Peter Bačík1
*, Jan Cempírek2,3
, Pavel Uher1
, Milan Novák4
, Daniel Ozdín1
, Jan Filip5
, Radek5
Škoda4
, Karel Breiter6
, Mariana Klementová7
and Rudolf Ďuďa8
6
7
1
Department of Mineralogy and Petrology, Comenius University, Mlynská dolina, 842 158
Bratislava, Slovakia9
2
Department of Mineralogy and Petrography, Moravian Museum, Zelný trh 6, 659 37 Brno,10
Czech Republic11
3
Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia,12
6339 Stores Road, Vancouver, BC, V6T 164 Canada13
4
Department of Geological Sciences, Masaryk University, Kotlářská 2, 611 37 Brno, Czech14
Republic15
5
Regional Centre of Advanced Technologies and Materials, Palacký University in Olomouc,16
17. listopadu 12, 771 46 Olomouc, Czech Republic17
6
Geological Institute of the Academy of Science of Czech Republic, v.v.i., Rozvojová 269,18
165 00 Praha 6, Czech Republic19
7
Institute of Physics of the AS CR, v.v.i., Na Slovance 2, 182 21 Praha 8, Czech Republic20
8
Bystrická 87, 040 11 Košice, Slovakia21
*E-mail: bacikp@fns.uniba.sk22
23
ABSTRACT24
Oxy-schorl (IMA 2011-011), ideally Na(Fe2+
2Al)Al6Si6O18(BO3)3(OH)3O, a new25
mineral species of the tourmaline supergroup, is described. In Zlatá Idka, Slovak Republic26
(type locality), fan-shaped aggregates of greenish black acicular crystals ranging up to 2 cm in27
size, forming aggregates up to 3.5 cm thick were found in extensively metasomatically altered28
metarhyolite pyroclastics with Qtz+Ab+Ms. In Přibyslavice, Czech Republic (co-type29
locality), abundant brownish black subhedral, columnar crystals of oxy-schorl, up to 1 cm in30
size, arranged in thin layers, or irregular clusters up to 5 cm in diameter, occur in a foliated31
muscovite-tourmaline orthogneiss associated with Kfs+Ab+Qtz+Ms+Bt+Grt. Oxy-schorl32
from both localities has a Mohs hardness of 7 with no observable cleavage and parting. The33
measured and calculated densities are 3.17(2) and 3.208 g cm-3
(Zlatá Idka) and 3.19(1) and34
2
3.198 g cm-3
(Přibyslavice), respectively. In plane polarized light, oxy-schorl is pleochroic –35
O = green to bluish-green, E = pale yellowish to nearly colorless (Zlatá Idka) and O = dark36
greyish-green, E = pale brown (Přibyslavice), uniaxial negative, ω = 1.663(2), ε = 1.641(2)37
(Zlatá Idka) and ω = 1.662(2); ε = 1.637(2) (Přibyslavice). Oxy-schorl is trigonal, space group38
R3m, Z=3, a = 15.916(3) Å, c = 7.107(1) Å, V = 1559.1(4) Å3
(Zlatá Idka) and a = 15.985(1)39
Å, c = 7.154(1) Å, V = 1583.1(2) Å3
(Přibyslavice). The composition (average of 5 electron40
microprobe analyses from Zlatá Idka and 5 from Přibyslavice) is (in wt.%): SiO2 33.8541
(34.57), TiO2 <0.05 (0.72), Al2O3 39.08 (33.55), Fe2O3 not determined (0.61), FeO 11.5942
(13.07), MnO <0.06 (0.10), MgO 0.04 (0.74), CaO 0.30 (0.09), Na2O 1.67 (1.76), K2O <0.0243
(0.03), F 0.26 (0.56), Cl 0.01 (<0.01), B2O3 (calc.) 10.39 (10.11), H2O (from the crystal-44
structure refinement) 2.92 (2.72), sum 99.29 (98.41) for Zlatá Idka and Přibyslavice (in45
parenthesis). A combination of EMPA, Mössbauer spectroscopy and crystal-structure46
refinement yields empirical formulae47
(Na0.591Ca0.103□0.306)Σ1.000(Al1.885Fe2+
1.108Mn0.005Ti0.002)Σ3.000(Al5.428Mg0.572)Σ6.000(Si5.506Al0.494)Σ648
.000O18(BO3)3(OH)3(O0.625OH0.236F0.136Cl0.003)Σ1.000 for Zlatá Idka, and49
(Na0.586Ca0.017K0.006□0.391)Σ1.000(Fe2+
1.879Mn0.015Al1.013Ti0.093)Σ3.00(Al5.732Mg0.190Fe3+
0.078)Σ6.000(Si50
5.944Al0.056)Σ6.000O18(BO3)3(OH)3(O0.579F0.307OH0.115)Σ1.000 for Přibyslavice. Oxy-schorl is51
derived from schorl end-member by the AlOFe-1(OH)-1 substitution. The studied crystals of52
oxy-schorl represent two distinct ordering mechanisms: disorder of R2+
and R3+
cations in53
octahedral sites and all O ordered in the W site (Zlatá Idka), and R2+
and R3+
cations ordered54
in the Y and Z sites and O disordered in the V and W sites (Přibyslavice).55
56
Keywords: oxy-schorl, tourmaline-supergroup minerals, new mineral, electron57
microanalysis, crystal-structure refinement, Přibyslavice, Zlatá Idka58
59
INTRODUCTION60
61
Minerals of tourmaline-supergroup are common in many geological environments.62
Complexity of their structure, variability of structural sites and chemical composition are63
manifested in a relatively large number of mineral species (Henry et al. 2011). Oxy-schorl,64
ideally Na(Fe2+
2Al)Al6Si6O18(BO3)3(OH)3O, is a new member of the alkali group and oxy-65
series of the tourmaline supergroup (sensu nomenclature of Henry et al. 2011). The coupled66
general substitution Y
R2+
+W
(OH) ↔ Y
Al+W
O derived from ideal schorl67
NaFe2+
3Al6Si6O18(BO3)3(OH)3OH and leading to the ideal oxy-schorl was discussed already68
3
by Foit and Rosenberg (1977); Povondra (1981), Povondra et al. (1985, 1987) and Foit (1989)69
published several chemical analyses of tourmalines corresponding to oxy-schorl including70
samples from the co-type locality Přibyslavice (Povondra et al. 1987). However, the term71
oxy-schorl was first introduced by Hawthorne and Henry (1999). Subsequently, oxy-schorl72
was described from several localities worldwide (e.g., Henry and Dutrow 2001, Novák et al.73
2004, Baksheev et al. 2011). Finally, oxy-schorl was defined as a potential new species of the74
tourmaline supergroup in the recent tourmaline nomenclature (Novák et al. 2009, Henry et al.75
2011). Oxy-schorl is likely quite a common mineral species; however, many tourmaline76
compositions are close to the simplified formula (Na0.5□0.5)Fe2+
2AlAl6Si6O18 (BO3)3 (OH)377
(OH0.5O0.5) (see e.g., Povondra 1981, Foit 1989, Novák et al. 2004) and owing to problems78
with the determination of H (and other light elements), exact classification of such schorlitic79
tourmalines is complicated.80
Oxy-schorl was approved by the Commission on New Minerals, Nomenclature and81
Classification of the International Mineralogical Association under the number IMA 2011–82
011. The holotype material from the type locality (Zlatá Idka, Slovak Republic) is preserved83
in the collection of the East-Slovak Museum, Košice, Slovakia (specimen number G-12760),84
and in the collection of Department of Mineralogy and Petrology, Comenius University,85
Bratislava, Slovakia (specimen number 7279). Oxy-schorl from co-type locality (Přibyslavice,86
Czech Republic) is deposited in the collections of the Department of Mineralogy and87
Petrography, Moravian Museum, Brno, Czech Republic, specimen number B10521. We88
provide here a description of physical, chemical and structural characteristics of oxy-schorl as89
a new mineral species.90
91
OCCURRENCE AND PHYSICAL PROPERTIES92
93
Oxy-schorl was found in fracture fillings cutting altered metarhyolite pyroclastics, in the94
abandoned Marianna adit, ca 2.5 km WNW from Zlatá Idka village (48°46'7"N, 20°57'50"E),95
Slovak Ore Mountains (Slovenské Rudohorie), near Košice, eastern Slovakia. The acid96
metapyroclastic rocks of Middle Ordovician age belong to the Bystrý Potok Formation of the97
Gelnica Group, Gemeric Superunit, Central Western Carpathians (Vozárová et al. 2010).98
Associated minerals of the host-rock include quartz, albite and muscovite. Oxy-schorl is99
probably a product of interaction between the metarhyolite pyroclastics and boron-enriched,100
hydrothermal fluids generated from adjacent Permian tourmaline-bearing leucogranites. Oxy-101
schorl from Zlatá Idka occurs in fan-shaped aggregates of greenish black acicular crystals102
4
ranging up to 2 cm in size, with aggregates up to 3.5 cm across. Tourmaline aggregates103
display chemical zoning in back-scattered electron (BSE) images (Fig. 1), locally with more104
Mg-rich (dravite to oxy-dravite) and also X-site vacant composition (“□-Fe-O root name”105
according to Henry et al., 2011) but oxy-schorl composition prevails.106
The second occurrence of oxy-schorl is in a foliated muscovite-tourmaline orthogneiss107
at Přibyslavice (Tisá skála outcrop, ~1 km ENE from Přibyslavice, 49°50'48"N, 15°25'1"E)108
near Kutná Hora, Central Bohemia Region, Czech Republic. The host Lower Palaeozoic109
muscovite-tourmaline alkali-feldspar granite was metamorphosed during the Variscan110
orogeny in the amphibolite facies (Breiter et al., 2010). The orthogneiss is composed of K-111
feldspar (orthoclase perthite), albite, quartz, muscovite, biotite, garnet and apatite with112
accessory zircon, magnetite, pyrite and ilmenite. Oxy-schorl from Přibyslavice formed as a113
primary magmatic mineral of the granite, but its composition was influenced by the later114
metamorphic processes (e.g., Povondra et al. 1987, 1998). It forms abundant subhedral,115
columnar homogeneous crystals, up to 1 cm in size, arranged in thin layers, or irregular116
clusters up to 5 cm in diameter.117
Oxy-schorl from both localities has vitreous luster and is translucent in thin edges, non-118
fluorescent and paramagnetic. Its Mohs hardness is 7, it is brittle and has conchoidal fracture;119
cleavage and parting were not observed. The streak is pale grey. The density was measured120
using a pycnometric method as 3.17(2) and 3.19(1) g cm-3
; calculated density using empirical121
formula and unit-cell data yields 3.208 and 3.198 g cm-3
for oxy-schorl from Zlatá Idka and122
Přibyslavice, respectively. Oxy-schorl is negative uniaxial with the following optical123
properties: ω = 1.663(2), ε = 1.641(2), birefrigence: 0.022 (589.9 nm) in Zlatá Idka and ω =124
1.662(2); ε = 1.637(2); birefringence: 0.025 (589.9 nm) in Přibyslavice: At both localities,125
oxy-schorl has distinct pleochroism; O = green to bluish-green, E = pale yellowish to nearly126
colorless (Zlatá Idka) and O = dark greyish-green, E = pale brown (Přibyslavice).127
128
ANALYTICAL METHODS129
130
Chemical composition131
Representative chemical analyses (5 from Zlatá Idka, 5 from Přibyslavice) were carried132
out on crystals used for structure refinement using a CAMECA SX100 electron microprobe133
(WDS mode, 15 kV, 10 and 20 nA, 5 μm beam diameter) and the following standards:134
almandine (Si Kα, Fe Kα), titanite (Ti Kα), sanidine (Al Kα, K Kα), chromite (Cr Kα),135
vanadinite (V Kα), spessartine (Mn Kα), MgO (Mg Kα), grossular (Ca Kα), albite (Na Kα),136
5
topaz (F Kα) and NaCl (Cl Kα). Detection limits of the measured elements vary between 0.01137
and 0.05 wt.%. Formulae of tourmalines were calculated on a basis of 15 Y+Z+T cations. H2O138
was calculated on the basis of electroneutral formula and structure refinement results. The139
presence of H2O was confirmed by IR spectroscopy. B2O3 was calculated from ideal formulae140
since the structure refinement data indicate full occupancy of the B-site and absence of [4]
B in141
the T-site. Ti and Cl were below detection limits (0.05 and 0.01 wt.%, respectively).142
Analytical data are given in Table 1. The content of Li in oxy-schorl from Zlatá Idka was143
determined by LA-ICP-MS analysis with a laser ablation system UP 213 (New Wave, USA)144
and quadrupole ICP-MS spectrometer Agilent 7500 CE (Agilent, Japan), at the Central145
European Institute of Technology, Masaryk University, Brno. It was always lower than a146
detection limit which corresponded to 0.04 wt. % Li2O. Oxy-schorl from Přibyslavice yielded147
Li2O ≤ 0.06 wt. % determined by wet chemical analysis (Povondra et al. 1987).148
149
Mössbauer spectroscopy150
The 57
Fe Mössbauer spectrum of powdered tourmaline (ground under acetone using an151
agate mortar) was acquired at constant acceleration mode using a 57
Co in Rh source at room152
temperature (293 K), at the Department of Nuclear Physics, Slovak Technical University,153
Bratislava, Slovakia (Zlatá Idka) and Centre for Nanomaterial Research, Faculty of Science,154
Palacký University in Olomouc (Přibyslavice). The isomer shift was calibrated against an α-155
Fe foil at room temperature. Spectra were fitted by Lorentz functions using the NORMOS156
program (Brand 1997) on the Zlatá Idka sample and CONFIT2000 program (Žák and157
Jirásková 2006) on the Přibyslavice sample. The fitting results are listed in Table 2.158
159
Infrared spectroscopy160
The FTIR spectrum of tourmaline from Přibyslavice was recorded using a Nicolet161
Nexus 670 spectrometer equipped with DTGS detector and XT-KBr beamsplitter. The sample162
was prepared by mixing 1 mg of powdered sample with 300 mg of KBr (dried beforehand at163
150 °C) and pressing in an evacuated die at 10 tons. A total of 32 scans in air were carried out164
for the sample in the wavenumber range 4000–400 cm–1
at a resolution of 4 cm–1
. The165
spectrum is shown in Figure 2, and a basic interpretation of the peaks (after Reddy et al. 2007)166
is listed in Table 3.167
168
Thermogravimetric analysis169
6
Thermal decomposition of oxy-schorl from Zlatá Idka and Přibyslavice was studied in170
an inert atmosphere (Ar) using a simultaneous thermal analyzer (STA 449 C Jupiter, Netzsch)171
including both thermogravimetric analysis (TGA) and differential scanning calorimetry172
(DSC) in the range of 30 - 1100 °C on the Department of Inorganic Chemistry, Comenius173
University in Bratislava (Zlatá Idka) and Department of Physics, Palacký University in174
Olomouc (Přibyslavice). The sample from Zlatá Idka was placed into Pt crucible with lid and175
dynamically heated with a heating rate of 20 Kmin-1
. TG correction: 020/5000 mg, DSC176
correction: 020/50 mV. The Přibyslavice sample was dynamically heated in open alumina177
crucible with a heating rate of 5 K/min.178
179
180
Powder X-ray diffraction181
Powder XRD measurements of oxy-schorl from Zlatá Idka were made on the BRUKER182
D8 Advance diffractometer (Department of Mineralogy and Petrology, Faculty of Natural183
Sciences, Comenius University in Bratislava, Slovakia) under the following conditions:184
Bragg-Brentano geometry, Cu anticathode, Ni Kβ filters, accelerating voltage: 40 kV, beam185
current: 40 mA. Data was obtained by the BRUKER LynxEye detector. The step size was186
0.01° 2θ, the step time was 5 s per one step, and the range of measurement was 4 – 65° 2 θ.187
Measured data was fitted and lattice parameters were refined with DIFFRACplus
TOPAS188
software (Bruker 2010) using pseudo-Voight function. Indexed diffraction data are listed in189
Table 4.190
Powder XRD data for oxy-schorl from Přibyslavice were recorded with a PANalytical191
X’Pert PRO MPD diffractometer (CoKα radiation) in Bragg-Brentano geometry, equipped192
with an X´Celerator detector and programmable divergence and diffracted beam anti-scatter193
slits. Diffraction pattern of the sample on a zero-background Si slide was scanned with a step194
size of 0.017° in 2θ range 5-90°. Data were indexed and refined with Stoe WinXPow package195
(version 1.06), using built-in Treor (Werner et al. 1985) and least-square refinement routines196
(Stoe & Cie 1999). Indexed diffraction data are listed in Table 5.197
198
Crystal structure refinement199
Single-crystal X-ray studies were carried out using a 4-circle Oxford Diffraction KM-200
4/Xcalibur diffractometer with a Sapphire2 (large Be window) CCD detector. The CrysAlis201
(Oxford Diffraction Ltd) and SHELXTL (PC Version) (Sheldrick 2000) program packages202
7
were used for data reduction and structure refinement, respectively, using neutral scattering203
factors and anomalous dispersion corrections. The structure of oxy-schorl was refined in R3m204
and converged to a final R index of 3.32% for Zlatá Idka and 1.91% for Přibyslavice data.205
Crystal and refinement details of tourmaline from Zlatá Idka are listed in Table 6, structural206
data are summarized in Tables 7 to 9 and bond-valence table is presented in Table 10. Crystal207
and refinement details of tourmaline from Přibyslavice are listed in Table 11 and structural208
data are summarized in Tables 12 to 14; its bond-valence table is presented in Table 15.209
210
211
212
RESULTS213
214
The samples of oxy-schorls from Zlatá Idka and Přibyslavice display some differences in215
chemical composition and site allocation. A combination of EMPA, Mössbauer spectroscopy216
and crystal-structure refinement yields following empirical formulae:217
(Na0.591Ca0.103 0.306)Σ1.000(Al1.885Fe2+
1.108Mn0.005Ti0.002)Σ3.000(Al5.428Mg0.572)Σ6.000(Si5.506Al0.494)Σ6.218
000O18(BO3)3(OH)3(O0.625OH0.236F0.136Cl0.003)Σ1.000 and219
(Na0.586Ca0.017K0.006□0.391)Σ1.000(Fe2+
1.879Mn0.015Al1.013Ti0.093)Σ3.00(Al5.732Mg0.190Fe3+
0.078)Σ6.000(Si220
5.944Al0.056)Σ6.000O18(BO3)3(OH)3(O0.579F0.307OH0.115)Σ1.000 for oxy-schorl from Zlatá Idka and221
Přibyslavice, respetively. They are in good agreement with the end-member formula222
Na(Fe2+
2Al)Al6Si6O18(BO3)3(OH)3O requiring SiO2 35.22, Al2O3 34.87, FeO 14.04, Na2O223
3.03, B2O3 10.20, H2O 2.64, total 100.00 wt.%. As suggested by the empirical formulae, oxy-224
schorl from Zlatá Idka is moderately disordered in the octahedral sites, while disorder in oxy-225
schorl from Přibyslavice is only negligible.226
The content of OHwas
calculated from electroneutral formula based on the crystal-227
structure refinement and Mössbauer spectroscopy data. Ferric iron takes only 4 % of all Fe in228
oxy-schorl from Přibyslavice and it was not detected in the sample from Zlatá Idka. The229
content of H2O was also measured using TGA; the TGA curve shows a mass change –2.96 %230
(Zlatá Idka) and –2.69 % (Přibyslavice) at ca. 950-1020 °C which corresponds to breakdown231
of the structure and release of water (bound in form of OH).
Reduced content of W
OH is also232
supported by the low intensity of the O–H stretching peak at 3628 cm-1
in the infrared233
absorption spectrum (Fig. 2). With regard to the possible chemical inhomogeneity of the234
samples (Fig. 1), the calculated H2O contents were preferred to the TGA results.235
8
Both tourmalines slightly differ structurally as represented by lattice parameters: a =236
15.9134(9) Å, c = 7.1012 Å, V = 1557.4(2) Å3
(powder XRD) and a = 15.916(3) Å, c =237
7.107(1) Å, V = 1559.1(4) Å3
(crystal-structure refinement) for Zlatá Idka and a =238
15.9865(8), c = 7.1608(3) Å, V = 1584.9(2) Å3
(powder XRD) and a = 15.985(1) Å, c =239
7.154(1) Å, V = 1583.1(2) Å3
(crystal-structure refinement) for Přibyslavice. Differences in240
lattice parameters result from different Fe2+
, Fe3+
and Al3+
occupancies in Y, Z and T sites in241
both tourmalines.242
Despite all differences between studied samples, they both belong to alkali group (Fig.243
3a), they represent oxy species (Fig. 3b) and their contents of Fe and Mg correspond to the244
composition of oxy-schorl (Fig. 3c).245
246
DISCUSSION AND CONCLUSIONS247
248
Oxy-schorl is chemically and structurally related to schorl. The name oxy-schorl has249
been abundantly used for tourmalines with the composition similar to schorl but containing250
more than 6.5 apfu Al, and O in the W site if known (e.g. Hawthorne & Henry 1999; Henry &251
Dutrow 2001; Buriánek & Novák 2004, 2007; Novák et al. 2004; Ertl et al. 2010a, 2010b;252
Baksheev et al. 2011; Bosi 2011). Since the current classification of the tourmaline253
supergroup (Henry et al. 2011) uses ordered formulae for tourmaline classification, it is254
generally possible to recognize oxy-schorl from electron microprobe data using the255
approximate limits: Na > 0.5 apfu, Al > 6.5 apfu, Fe > Mg and F < 0.5 apfu . However,256
ordering of ions in the structure of different samples can be variable. In the tourmaline257
structure the W site is located on the 3-fold axis passing through the unit cell, and surrounded258
by three Y sites (Hawthorne 1996, 2002). From the crystallographic point of view there are259
two different possible arrangements: 1) W = OH or F with valence bond ca. 0.33 vu; 2) W = O260
- valence bond is ca. 0.67 vu (vu = valence units, Hawthorne 1996, 2002). The substitution of261
O for OH results in the increase of charge requirements in the neighboring Y sites and the262
substitution of Al for divalent cations, or disorder of divalent and trivalent cations among the263
octahedral Y and Z sites. If the W site is fully occupied by O, the structural arrangements with264
3Y
R2+
or 2Y
R2+
+Y
R3+
cations are less favorable than the arrangements with 3Y
R3+
or265
2Y
R3+
+Y
R2+
(Hawthorne 2002). Therefore, in natural samples with the mixed occupancy of the266
W site, combination of 2Y
R2+
+Y
R3+
and 2Y
R3+
+Y
R2+
arrangements is the most probable.267
The crystal-structure refinement of oxy-schorl from Zlatá Idka showed that significant268
amount of divalent cations is allocated in the Z site, resulting in the content of Y
Al3+
of 1.885269
9
apfu, the possible Y site short-range arrangements favor dominant O2in
W site. The observed270
Al-Mg disorder in tourmalines was already studied (e.g., Grice and Ercit 1993; Hawthorne et271
al. 1993; Bloodaxe et al. 1999; Bosi & Lucchesi 2004). Although the Fe2+
-Al3+
disorder could272
be allowed by local short- and long-range arrangements (Bosi 2011), Mg is more likely273
substituting for Al in the Z site due to its smaller ionic radii similar to Al3+
, as was observed in274
the oxy-schorl from Zlatá Idka. In contrast, the oxy-schorl from Přibyslavice shows only275
negligible disorder of Al and (Mg,Fe) in octahedral sites; the vast majority of R2+
(Fe2+
>>276
Mg) is allocated to the Y site. However, the calculated bond valence values for the O1 and O3277
sites suggest a disorder of O and OH among the anion sites V and W (Table 15).278
The formula of end-member oxy-schorl may be expressed either as279
Na(Fe2+
Al2)(Fe2+
Al5)Si6O18(BO3)3(OH)3O with cations disordered in two structural sites, or280
with cations disordered only in one structural site such as281
NaAl3(Al4Fe2+
2)Si6O18(BO3)3(OH)3O and Na(Fe2+
2Al)Al6Si6O18(BO3)3(OH)3O – the formula282
used in the valid nomenclature (Henry et al. 2011). It recommends allocation of trivalent283
cations to the Z site initially, followed by assignment of the remainder of R3+
to Y site.284
Nevertheless, this end-member formula could not be stable owing to the local charge285
requirements, and the first formula with cations disordered in two sites is closely approaching286
the composition of natural samples (Hawthorne 2002).287
These two studied oxy-schorl samples confirm the two distinct ordering mechanisms in288
natural oxy-tourmalines: (1) disorder of divalent and trivalent cations in octahedral sites and289
all O ordered in the W site (favored by the Mg-bearing oxy-schorl from Zlatá Idka); (2)290
cations ordered in the Y and Z sites and O disordered in the V and W sites (in Fe-dominant291
oxy-schorl from Přibyslavice). The elevated content of Mg in oxy-schorl from Zlatá Idka (Fig.292
3c, Table 1) very likely facilitates higher degree of disorder in Y and Z sites and higher293
ordering in W site relative to Mg-poor oxy-schorl from Přibyslavice. Since formula with294
ordered V and W sites is recommended for the classification purposes (Henry et al. 2011),295
both compositions result in the same ordered formula that meets nomenclatural requirements296
for oxy-schorl.297
The presence of oxy-schorl does not necessary imply oxidizing geological environment.298
Mineral association in the Přibyslavice orthogneiss suggests more reductive conditions299
documented by magnetite and pyrite (e.g., Povondra et al. 1987, 1998). Thus the reasons of300
the formation of oxy-schorl in spite of schorl are different than high oxygen fugacity. It could301
take a part in oxy-tourmalines with an increased proportion of Fe3+
as buergerite (e.g. Donnay302
et al. 1966; Grice and Ercit 1993) or povondraite component (e.g. Grice et al. 1993; Bačík et303
10
al. 2008; Baksheev et al. 2011; Novák et al. 2011), respectively, in which the deprotonization304
is driven by Y
Fe2+
+ W+V
OH↔
Y
Fe3+
+ W+V
O2reaction
(Pieczka and Kraczka 2004; Bačík et305
al. 2011). In contrast, the deprotonization was driven by Y
R2+
+ W+V
OH↔
Y
Al + W+V
O2-
306
reaction in studied samples of oxy-schorl from both localities. Consequently, the307
deprotonization in studied oxy-schorls was likely the result of local charge-balance308
requirements owing to the excess of Al and the formation of Al-enriched oxy-schorl is the309
result of the specific geochemistry of the host rock.310
311
Acknowledgement:312
Authors would like to thank Tomáš Vaculovič for LA-ICP-MS analysis. This work was313
supported by projects APVV-VVCE-0033-07 to PB, PU and DO and GAP210/10/0743 to JC,314
JF, MN and RŠ and by the Operational Program Research and Development for Innovations -315
European Regional Development Fund (Project No. CZ.1.05/2.1.00/03.0058 of the Ministry316
of Education, Youth and Sports of the Czech Republic) to JF. We thank Martin Kunz and317
Fernando Colombo for editorial handling and for their detailed reviews and fruitful318
discussion.319
320
321
11
REFERENCES:322
323
Bačík, P., Uher, P., Sýkora, M., and Lipka, J. (2008) Low-Al tourmalines of the schorl-324
dravite-povondraite series in redeposited tourmalinites from the Western Carpathians,325
Slovakia. Canadian Mineralogist, 46, 1117–1129.326
Bačík, P., Ozdín, D., Miglierini, M., Kardošová, P., Pentrák, M., and Haloda, J. (2011)327
Crystallochemical effects of heat treatment on Fe-dominant tourmalines from Dolní328
Bory (Czech Republic) and Vlachovo (Slovakia). Physics and Chemistry of Minerals,329
38, 599–611.330
Baksheev, I.A., Prokof’ev, V.Y., Yapaskurt, V.O., Vigasina, M.F., Zorina, L.D., and331
Solov’ev, V.N. (2011) Ferric-iron-rich tourmaline from the Darasun gold deposit,332
Transbaikalia, Russia. Canadian Mineralogist, 49, 263–276.333
Bloodaxe, E.S., Hughes, J.M., Dyar, M.D., Grew, E.S., and Guidotti, C.V., (1999) Linking334
structure and chemistry in the schorl-dravite series. American Mineralogist, 84, 922–335
928.336
Bosi, F. (2011) Stereochemical constraints in tourmaline: From a short-range to a long-range337
structure. Canadian Mineralogist, 49, 17–27.338
Bosi, F. and Lucchesi S. (2004) Crystal chemistry of the schorl-dravite series. European339
Journal of Mineralogy, 16, 335–344340
Brand, R.A. (1997) NORMOS: Mossbauer fitting program, version 1997, unpublished.341
Breiter, K., Škoda, R. and Novák, M. (2010) Field stop 5: Přibyslavice near Čáslav – complex342
of peraluminous phosphorus-rich tourmaline-bearing orthogneiss, and associated granite343
and pegmatite with garnet, tourmaline, and primary Fe-Mn phosphates. In: Novák, M.344
and Cempírek, J. (eds) Granitic pegmatites and mineralogical museums in the Czech345
Republic. Acta Mineralogica-Petrographica, Field Guide Series, 6, 29-36.346
Bruker (2010) DIFFRACplus TOPAS. http://www.bruker-axs.de/topas.html347
Buriánek, D. and Novák, M. (2004) Morphological and compositional evolution of tourmaline348
from nodular granite at Lavičky near Velké Meziříčí, Moldanubicum, Czech Republic.349
Journal of Czech Geological Society, 49, 81–90.350
Buriánek, D. and Novák, M. (2007) Compositional evolution and substitutions in351
disseminated and nodular tourmaline from leucocratic granites: Examples from the352
Bohemian Massif, Czech Republic. Lithos, 95, 148–164.353
12
Donnay, G., Ingamells, C. O., and Mason B. (1966) Buergerite, a new species of tourmaline.354
American Mineralogist, 51, 198–199.355
Ertl, A., Marschall, H.R., Giester, G., Henry, D.J., Schertl, H.P., Ntaflos, T ., Luvizotto, G.L.,356
Nasdala, L., and Tillmanns, E. (2010a): Metamorphic ultrahigh-pressure tourmaline:357
Structure, chemistry, and correlations to P-T conditions. American Mineralogist, 95, 1–358
10.359
Ertl, A., Rossman, G.R., Hughes, J.M., London, D., Wang, Y., O'Leary, J.A., Dyar, M.D.,360
Prowatke, S., Ludwig, T., and Tillmanns, E. (2010b) Tourmaline of the elbaite-schorl361
series from the Himalaya Mine, Mesa Grande, California: A detailed investigation.362
American Mineralogist, 95, 24–40.363
Foit, F.F. (1989) Crystal chemistry of alkali-deficient schorl and tourmaline structural364
relationships. American Mineralogist, 74, 422–431.365
Foit, F.F. Jr. and Rosenberg, P.E. (1977) Coupled substitutions in the tourmaline group.366
Contributions to Mineralogy and Petrology, 62, 109–127.367
Grice, J.D. and Ercit, T.S. (1993) Ordering of Fe and Mg in tourmaline: The correct formula.368
Neues Jahrbuch fur Mineralogie Abhandlungen, 165, 245–266.369
Grice, J. D., Ercit, T. S., and Hawthorne, F. C. (1993) Povondraite, a redefinition of the370
tourmaline ferridravite. American Mineralogist, 78, 433–436.371
Hawthorne, F.C. (1996) Structural mechanisms for light elements in tourmaline. Canadian372
Mineralogist, 34, 123–132.373
Hawthorne, F.C. (2002) Bond-valence constraints on the chemical composition of tourmaline.374
Canadian Mineralogist, 40, 789–797.375
Hawthorne, F.C., MacDonald, D.J., and Burns, P.C. (1993) Reassignment of cation site376
occupancies in tourmaline: Al-Mg disorder in the crystal structure of dravite. American377
Mineralogist, 78, 265–270.378
Hawthorne, F.C. and Henry, D.J. (1999) Classification of the minerals of the tourmaline379
group. European Journal of Mineralogy, 11, 201–215.380
Henry, D.J. and Dutrow, B. (2001) Compositional zoning and element partitioning of381
nickeloan tourmaline in a metamorphosed karstbauxite from Samos, Greece. American382
Mineralogist, 86, 1130–1142.383
Henry, D., Novák, M., Hawthorne, F.C., Ertl, A., Dutrow, B., Uher, P., and Pezzotta, F.384
(2011) Nomenclature of the tourmaline supergroup-minerals. American Mineralogist,385
96, 895–913.386
13
Novák, M., Henry, D., Hawthorne F.C., Ertl, A., Uher, P., Dutrow, B., and Pezzotta, F. (2009)387
Nomenclature of the tourmaline-group minerals. Report of the Subcommittee on388
Tourmaline Nomenclature to the International Mineralogical Association’s Commission389
on New Minerals, Nomenclature and Classification.390
Novák, M., Povondra, P., and Selway, J.B. (2004) Schorl-oxy-schorl to dravite-oxy-dravite391
tourmaline from granitic pegmatites; examples from the Moldanubicum, Czech392
Republic. European Journal of Mineralogy, 16, 323–333.393
Novák, M., Škoda, R., Filip, J., Macek, I., and Vaculovič, T. (2011) Compositional trends in394
tourmaline from intragranitic NYF pegmatites of the Třebíč Pluton, Czech Republic;395
electron microprobe, Mössbauer and LA-ICP-MS study. Canadian Mineralogist, 49,396
359–380.397
Povondra, P. (1981) The crystal chemistry of tourmalines of the schorl-dravite series. Acta398
Universitatis Carolinae, Geologica, 223–264.399
Povondra, P., Čech, F., and Staněk, J. (1985) Crystal chemistry of elbaites from some400
pegmatites of the Czech Massif. Acta Universitatis Carolinae, Geologica, 1–24.401
Povondra, P., Lang, M., Pivec, E., and Ulrych, J. (1998) Tourmaline from the Přibyslavice402
peraluminous alkali-feldspar granite, Czech Republic. Journal of Czech Geological403
Society, 43, 3–8.404
Povondra, P., Pivec, E., Čech, F., Lang, M., Novák, F., Prachař, I., and Ulrych, J. (1987)405
Přibyslavice peraluminous granite. Acta Universitatis Carolinae, Geologica, 183–283.406
Reddy, B.J., Frost, R.L., Martens, W.N., Wain, D.L. and Kloprogge, J.T. (2007)407
Spectroscopic characterization of Mn-rich tourmalines. Vibrational Spectroscopy, 44,408
42–49.409
Sheldrick, G. M. (2000) SHELXTL. Version 6.10. Bruker AXS Inc., Madison, Wisconsin,410
USA411
Stoe & Cie (1999) WinXPow. Stoe & Cie, Darmstadt, Germany.412
Vozárová, A., Šarinová, K., Larionov, A., Presnyakov, S., and Sergeev, S. (2010) Late413
Cambrian/Ordovician magmatic arc type volcanism in the Southern Gemericum414
basement, Western Carpathians, Slovakia: U-Pb (SHRIMP) data from zircons.415
International Journal of Earth Sciences, 99 (Suppl. 1), 17–37.416
Werner, P.-E., Eriksson, L., and Westdahl, M. (1985) TREOR, a semi-exhaustive trial-and-417
error powder indexing program for all symmetries. Journal of Applied Crystallography,418
18, 367-370.419
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Žák, T. and Jirásková, Y. (2006) CONFIT: Mössbauer spectra fitting program. Surface and420
Interface Analysis, 38, 710–714.421
422
423
424
15
425
Figure 1. BSE image of oxy-schorl from Zlatá Idka. The zoning is given by the variation in426
Fe, Mg and Al content; dark grey zone corresponds to transitional oxy-schorl to “□-Fe-O root427
name” tourmaline composition.428
429
Figure 2. FTIR spectrum of oxy-schorl from Přibyslavice.430
431
Figure 3. Ternary diagrams for minerals of tourmaline group used for determination of432
dominant occupancy at the X (a), W (b) and Y site (c).433
434
16
TABLE 1. CHEMICAL COMPOSITION AND FORMULA OF OXY-SCHORL FROM ZLATÁ IDKA AND435
PŘIBYSLAVICE436
437
Zlatá Idka Přibyslavice
SiO2 wt% 33.10 Si apfu 5.506 SiO2 wt% 34.57 Si apfu 5.944
TiO2 0.02 Z
Al 0.494 TiO2 0.72 Z
Al 0.056
B2O3* 10.45 Sum T 6.000 B2O3* 10.11 Sum T 6.000
Al2O3 39.81 Al2O3 33.55
FeO 7.97 B 3.000 Fe2O3 0.61 B 3.000
MgO 2.31 FeO 13.07
MnO 0.03 Z
Al 5.428 MnO 0.10 Z
Al 5.732
CaO 0.58 Z
Mg 0.572 MgO 0.74 Z
Mg 0.190
Na2O 1.83 Sum Z 6.000 CaO 0.09 Fe3+
0.078
F 0.26 K2O 0.03 Sum Z 6.000
Cl 0.01 Ti 0.002 Na2O 1.76
H2O** 2.92 Y
Al 1.885 Cl 0.00 Y
Al 1.013
O=F 0.11 Fe2+
1.108 F 0.56 Ti4+
0.093
Total 99.18 Mn 0.005 H2O** 2.72 Fe2+
1.879
Sum Y 3.000 -O = F,Cl -0.24 Mn2+
0.015
Total 98.39 Sum Y 3.000
Ca 0.103
Na 0.591 Ca 0.017
□ 0.306 Na 0.586
Sum X 1.000 K 0.006
□ 0.391
V
OH 3.000 Sum X 1.000
W
OH 0.236
V
OH 3.000
F 0.136
Cl 0.003
W
OH 0.115
O 0.625 O 0.579
Sum W 1.000 F 0.307
* calculated by structural refinement; ** calculated on the basis of electroneutral formula and438
structure refinement results439
440
17
441
TABLE 2. HYPERFINE PARAMETERS (MÖSSBAUER SPECTROSCOPY) OF OXY-SCHORL442
443
Isomer shift Quadrupole
splitting
Assignment Relative
abundance
(mm s-1
) (mm s-1
) (%)
Zlatá Idka 0.98 2.45 Y1
Fe2+
43
0.98 2.13 Y2
Fe2+
13
0.98 1.64 Y3
Fe2+
44
Přibyslavice 1.09 2.47 Y1
Fe2+
37
1.08 2.15 Y2
Fe2+
35
1.04 1.58 Y3
Fe2+
25
0.37 0.32 Y
Fe3+
4
444
445
TABLE 3. IR SPECTROSCOPIC DATA FOR OXY-SCHORL FROM PŘIBYSLAVICE446
447
Peak [cm-1
] Assignment
400 – 840 lattice vibrations
840 – 1200 Si6O18 stretching vibrations
(Fe,Mg)-OH bending vibrations
1200 – 2000 BO3 stretching vibrations
~ 3000 – 3600 O–H stretching (at O3; overlapping peaks
from variable configurations of Y- and Zsite
cations around O3)
3600 – 3700 O–H stretching (at O1; overlap of peaks
from variable configurations of Y-site
cations)
448
449
18
TABLE 4. POWDER X-RAY DIFFRACTION DATA FOR OXY-SCHORL FROM ZLATÁ IDKA.450
THE 5 STRONGEST LINES ARE HIGHLIGHTED451
452
h k l dobs. [Å] I [%] dcalc. [Å] h k l dobs. [Å] I [%] dcalc. [Å]
1 1 0 7.957 10 7.957 1 6 1 2.01524 15 2.01524
1 0 1 6.312 49 6.312 4 4 0 1.98918 12 1.98918
0 2 1 4.9452 27 4.9452 3 4 2 1.90993 23 1.90993
3 0 0 4.5938 28 4.5938 3 5 1 1.89721 11 1.89721
2 1 1 4.2001 52 4.2001 1 4 3 1.86002 11 1.86001
2 2 0 3.9784 100 3.9784 6 2 1 1.84547 12 1.84548
0 1 2 3.4383 64 3.4383 7 1 0 1.82539 9 1.82540
1 3 1 3.3657 25 3.3657 6 1 2 1.80857 9 1.80857
2 0 2 3.1562 18 3.1562 3 3 3 1.76601 10 1.76601
4 0 1 3.0998 20 3.0998 1 0 4 1.76075 10 1.76074
4 1 0 3.0074 25 3.0074 6 3 0 1.73629 9 1.73630
1 2 2 2.9338 52 2.9338 5 3 2 1.72180 10 1.72180
3 2 1 2.8883 21 2.8883 0 2 4 1.71916 10 1.71915
3 3 0 2.6522 16 2.6522 5 4 1 1.71245 9 1.71246
3 1 2 2.6014 18 2.6014 2 6 2 1.68284 10 1.68285
0 5 1 2.5695 62 2.5695 2 1 4 1.68038 13 1.68037
0 4 2 2.47260 15 2.47260 0 8 1 1.67412 9 1.67412
2 4 1 2.44517 15 2.44518 0 6 3 1.64840 14 1.64840
0 0 3 2.36707 22 2.36705 2 7 1 1.63825 12 1.63825
2 3 2 2.36122 23 2.36121 5 2 3 1.61413 8 1.61412
5 1 1 2.33730 21 2.33730 1 3 4 1.61010 9 1.61010
6 0 0 2.29690 13 2.29691 5 5 0 1.59134 13 1.59134
1 1 3 2.26880 12 2.26878 4 5 2 1.58016 10 1.58016
5 2 0 2.20679 12 2.20680 4 0 4 1.57812 10 1.57811
5 0 2 2.17725 17 2.17725 8 1 1 1.57293 10 1.57293
4 3 1 2.15845 16 2.15846 8 0 2 1.54989 8 1.54989
3 0 3 2.10416 16 2.10415 3 2 4 1.54796 8 1.54796
4 2 2 2.10005 17 2.10004 4 6 1 1.54306 9 1.54307
2 2 3 2.03423 27 2.03422 9 0 0 1.53127 9 1.53127
1 5 2 2.03051 31 2.03051
453
19
TABLE 5. POWDER X-RAY DIFFRACTION DATA FOR OXY-SCHORL FROM PŘIBYSLAVICE.454
THE 5 STRONGEST LINES ARE HIGHLIGHTED455
456
h k l dobs. [Å] I [%] dcalc. [Å] h k l dobs. [Å] I [%] dcalc. [Å]
1 0 1 6.3637 75 6.3604 0 2 4 1.7333 2.0 1.7332
0 2 1 4.9775 28 4.977 5 3 2 1.7312 1.5 1.7312
3 0 0 4.6157 12 4.6149 2 6 2 1.692 1.9 1.692
2 1 1 4.2254 48 4.225 6 0 3 1.6589 14.1 1.659
2 2 0 3.9969 52 3.9966 2 7 1 1.6461 6.7 1.6461
0 1 2 3.4664 100 3.4664 1 3 4 1.6227 0.6 1.6225
1 3 1 3.3839 6 3.384 5 5 0 1.5986 7.3 1.5987
2 0 2 3.1803 1 3.1802 4 0 4 1.5896 2.4 1.5901
4 0 1 3.1164 2 3.1163 8 1 1 1.5804 0.7 1.5804
4 1 0 3.0211 8 3.0212 3 2 4 1.5591 1.0 1.5595
1 2 2 2.9549 79 2.9549 4 6 1 1.5504 1.9 1.5504
3 2 1 2.9035 5 2.9034 9 0 0 1.5383 1.8 1.5383
3 1 2 2.6188 3 2.6186 7 2 2 1.5293 1.6 1.5293
0 5 1 2.5826 65 2.5826 7 3 1 1.5221 0.8 1.5221
0 4 2 2.4883 3 2.4885 8 2 0 1.5105 2.6 1.5106
2 4 1 2.4576 3 2.4575 0 5 4 1.5033 9.3 1.5034
0 0 3 2.3868 12 2.3869 2 4 4 1.4772 2.3 1.4775
2 3 2 2.3761 16 2.376 5 1 4 1.4528 10.2 1.4529
5 1 1 2.349 9 2.349 7 4 0 1.4355 1.6 1.4356
6 0 0 2.3072 1 2.3075 0 1 5 1.4247 3.1 1.4246
1 1 3 2.2869 1 2.2871 6 5 1 1.4224 3.5 1.4224
5 2 0 2.2171 1 2.2169 4 3 4 1.4072 6.6 1.4071
5 0 2 2.1903 9 2.1904 3 8 1 1.3793 0.6 1.3794
4 3 1 2.1692 7 2.1691 10 0 1 1.3593 3.8 1.3593
3 0 3 2.12 11 2.1201 9 1 2 1.345 2.0 1.345
4 2 2 2.1125 4 2.1125 6 6 0 1.3321 1.2 1.3322
2 2 3 2.0494 12 2.0493 7 0 4 1.3277 2.8 1.3273
1 5 2 2.0423 31 2.0424 0 4 5 1.3234 1.7 1.3234
1 6 1 2.0252 5 2.0251 10 1 0 1.314 3.5 1.3141
4 4 0 1.9983 2 1.9983 8 3 2 1.3087 1.0 1.3085
3 4 2 1.9207 17 1.9208 2 3 5 1.3055 1.2 1.3056
7 0 1 1.9065 2 1.9064 9 0 3 1.2931 0.5 1.293
4 1 3 1.8729 8 1.8729 0 10 2 1.2913 0.7 1.2913
6 2 1 1.8545 4 1.8544 8 4 1 1.2869 0.8 1.2869
7 1 0 1.834 1 1.8338 9 3 0 1.2799 1.3 1.2799
6 1 2 1.8186 2 1.8187 8 2 3 1.2765 1.0 1.2764
3 3 3 1.7779 3 1.7779 5 0 5 1.272 4.1 1.2721
1 0 4 1.7754 3 1.7754
457
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TABLE 6. CRYSTAL AND REFINEMENT DATA FOR OXY-SCHORL FROM ZLATÁ IDKA458
459
a = 15.916(3) Å Space group: R3m
c = 7.1071(12) Å Mo Kα radiation, λ = 0.71073 Å
V = 1559.1(4) Å3
Cell parameters from 1225 reflections
Z = 3
Elongated grain, brown 0.20 × 0.10 × 0.10 mm
θ = 3.2–36.1° (-26≤ h ≤17, -17≤ k ≤26, -11≤ l ≤11)
µ = 1.68 mm−1
F(000) = 1468
T = 293 K
Reflections measured: 3174
Independent reflections: 1474
Reflections > 2σ : 1111
R [F2
> 2σ(F2
)] = 0.034 (Δ/σ)max = <0.001
wR(F2
) = 0.066 extinction coef. : none
S = 0.84 92 parameters refined
Δρmax = 0.67 e Å−3
Δρmin = −0.38 e Å−3
460
461
TABLE 7. FRACTIONAL ATOMIC COORDINATES AND ISOTROPIC OR EQUIVALENT ISOTROPIC462
DISPLACEMENT PARAMETERS (Å2
) OF OXY-SCHORL FROM ZLATÁ IDKA463
464
x y z Uiso*/Ueq Occ. (<1)
Na 0.0000 0.0000 0.0825 (5) 0.0229 (12) 0.859 (14)
Y (Al) 0.12237 (7) 0.06118 (4) 0.50346 (13) 0.0119 (3) 0.799 (7)
Y (Fe) 0.12237 (7) 0.06118 (4) 0.50346 (13) 0.0119 (3) 0.201 (7)
Z (Al) 0.29700 (6) 0.36937 (6) 1.14311 (12) 0.0104 (2) 0.959 (5)
Si 0.19214 (5) 0.19002 (5) 0.86941 (10) 0.0080 (2) 0.899 (5)
O1 0.0000 0.0000 0.6394 (8) 0.0269 (12)
O2 0.06060 (11) 0.1212 (2) 0.3556 (4) 0.0210 (7)
O3 0.2620 (2) 0.13101 (12) 0.3745 (4) 0.0189 (7)
O4 0.1869 (2) 0.09346 (11) 0.9640 (4) 0.0198 (6)
O5 −0.1883 (2) −0.09417 (11) −0.0580 (4) 0.0192 (6)
O6 0.19549 (14) 0.18438 (14) 0.6403 (3) 0.0150 (4)
O7 0.28759 (14) 0.28731 (13) 0.9447 (3) 0.0142 (4)
O8 0.20909 (14) 0.26975 (14) 1.3046 (3) 0.0145 (4)
B 0.10971 (18) 0.2194 (4) 0.3182 (6) 0.0142 (8)
465
466
467
468
21
TABLE 8. ATOMIC DISPLACEMENT PARAMETERS (Å2
) OF OXY-SCHORL FROM ZLATÁ IDKA469
470
U11
U22
U33
U12
U13
U23
Na 0.0223 (15) 0.0223 (15) 0.024 (2) 0.0111 (8) 0.000 0.000
Y (Al) 0.0113 (5) 0.0098 (4) 0.0151 (5) 0.0057 (2) −0.0019 (3) −0.00095 (17)
Y (Fe) 0.0113 (5) 0.0098 (4) 0.0151 (5) 0.0057 (2) −0.0019 (3) −0.00095 (17)
Z (Al) 0.0113 (4) 0.0109 (4) 0.0098 (4) 0.0060 (3) 0.0001 (3) −0.0004 (3)
Si 0.0081 (4) 0.0082 (4) 0.0076 (3) 0.0041 (3) −0.0002 (3) −0.0008 (3)
O1 0.0314 (19) 0.0314 (19) 0.018 (3) 0.0157 (9) 0.000 0.000
O2 0.0251 (13) 0.0147 (14) 0.0197 (14) 0.0073 (7) 0.0001 (6) 0.0002 (12)
O3 0.0291 (17) 0.0171 (11) 0.0144 (13) 0.0146 (8) 0.0005 (12) 0.0003 (6)
O4 0.0243 (16) 0.0168 (10) 0.0208 (14) 0.0121 (8) −0.0001 (12) 0.0000 (6)
O5 0.0250 (16) 0.0188 (11) 0.0160 (13) 0.0125 (8) 0.0018 (11) 0.0009 (6)
O6 0.0165 (10) 0.0169 (10) 0.0111 (8) 0.0080 (8) 0.0012 (7) 0.0008 (7)
O7 0.0135 (9) 0.0138 (9) 0.0133 (8) 0.0053 (8) 0.0002 (7) −0.0003 (7)
O8 0.0136 (9) 0.0152 (10) 0.0153 (9) 0.0075 (8) −0.0001 (7) 0.0018 (7)
B 0.0172 (16) 0.015 (2) 0.0094 (16) 0.0077 (10) −0.0002 (7) −0.0004 (14)
471
472
TABLE 9. SELECTED BOND LENGTHS FOR OXY-SCHORL FROM ZLATÁ IDKA473
474
Site Anion Distance s.d. Site Anion Distance s.d.
X O2i
2.561 (4) Z O6vii
1.869 (2)
O2ii
2.561 (4) O7 1.876 (2)
O2 2.561 (4) O8 1.889 (2)
O4iii
2.710 (3) O8viii
1.918 (2)
O4iv
2.710 (3) O7ix
1.925 (2)
O4v
2.710 (3) O3vii
1.9890 (15)
O5i
2.781 (3) avg. 1.911
O5ii
2.781 (3)
O5 2.781 (3) T O7 1.625 (2)
avg. 2.684 O5x
1.6298 (12)
O6 1.633 (2)
Y O1 1.944 (3) O4 1.6412 (15)
O6vi
1.965 (2) 1.632
O6 1.965 (2)
O2 1.981 (2) B O2 1.380 (6)
O2i
1.981 (2) O8iii
1.373 (3)
O3 2.132 (3) O8xi
1.373 (3)
avg. 1.995 avg. 1.375
Symmetry codes: (i) −x+y, −x, z; (ii) −y, x−y, z; (iii) x, y, z−1; (iv) −y, x−y, z−1; (v) −x+y,
−x, z−1; (vi) x, x−y, z; (vii) −x+y+1/3, −x+2/3, z+2/3; (viii) −x+y+1/3, −x+2/3, z−1/3; (ix)
−y+2/3, x−y+1/3, z+1/3; (x) −x+y, −x, z+1; (xi) −x+y, y, z−1.
475
22
TABLE 10. BOND VALENCE TABLE FOR OXY-SCHORL FROM ZLATÁ IDKA476
477
X Y Z B T ∑
Na0.591Ca0.10
3
K0.004□0.302
Al1.808
Fe2+
1.105
Ti0.002
Mn0.005
Mg0.079
Al5.5 Mg0.5 B Si5.509 Al0.491
O1*† 0.478 1.435
O2 0.098 0.450 0.946 1.973
0.098 0.450
0.098
O3* 0.299 0.405 1.109
O4 0.065 0.960 1.986
0.065
0.065
O5 0.054 0.991 2.035
0.054
0.054
O6 0.469 0.560 0.982 2.012
0.469
O7 0.550 1.003 2.035
0.482
O8 0.531 0.995 2.016
0.491 0.995
∑ 0.649 2.616 3.019 2.965 3.937
IC(avg) 0.801 2.603 2.917 3.000 3.918
Δ 0.152 -0.013 -0.102 0.035 -0.019
IC(avg) = average ionic charge of atoms occupying the site. *Hydrogen bond donor.
† content of the O1 site is: O0.536 OH0.328 F0.136.
478
479
480
481
482
483
23
TABLE 11. CRYSTAL AND REFINEMENT DATA FOR OXY-SCHORL FROM PŘIBYSLAVICE484
485
486
a = 15.9853(12) Å Space group: R3m
c = 7.1538(6) Å Mo Kα radiation, λ = 0.71073 Å
V = 1583.1(2) Å3
Cell parameters from 2936 reflections
Z = 3
Elongated grain, brown 0.30 × 0.10 × 0.10 mm
θ = 2.9–36.1° (-26≤ h ≤18, -25≤ k ≤23, -8≤ l ≤11)
µ = 2.20 mm−1
F(000) = 1501
T = 293 K
Reflections measured: 4166
Independent reflections: 1380
Reflections > 2σ : 1285
R [F2
> 2σ(F2
)] = 0.0191 (Δ/σ)max = 0.001
wR(F2
) = 0.0400 extinction coef. = 0.00058(10)
S = 0.98 96 parameters refined
Δρmax = 0.65 e Å−3
Δρmin = −0.49 e Å−3
487
488
TABLE 12. FRACTIONAL ATOMIC COORDINATES AND ISOTROPIC OR EQUIVALENT ISOTROPIC489
DISPLACEMENT PARAMETERS (Å2
) FOR OXY-SCHORL FROM PŘIBYSLAVICE490
491
Site x/a y/b z/c Uiso*/Ueq Occup.
X Na 0 0 0.9019 (5) 0.0266 (11) 0.676(10)
Y Fe 0.87496 (3) 0.937481 (16) 0.50264 (6) 0.00869 (12) 0.621(4)
Al 0.87496 (3) 0.937481 (16) 0.50264 (6) 0.00869 (12) 0.379(4)
Z Al 0.70355 (3) 0.63191 (3) −0.14783 (6) 0.00590 (13) 0.974(3)
Fe 0.70355 (3) 0.63191 (3) −0.14783 (6) 0.00590 (13) 0.026(3)
T Si 0.80806 (3) 0.81008 (3) 0.12963 (6) 0.00569 (10)
O1 O1 0 0 0.3485 (5) 0.0363 (9) 0.69**
F 0 0 0.3485 (5) 0.0363 (9) 0.31**
O2 O2 0.93822 (6) 0.87643 (12) 0.6435 (3) 0.0151 (4)
O3 O3 0.73144 (14) 0.86572 (7) 0.6201 (2) 0.0123 (3)
O4 O4 0.81267 (12) 0.90634 (6) 0.0387 (2) 0.0103 (3)
O5 O5 0.18631 (12) 0.09316 (6) 0.0618 (2) 0.0104 (3)
O6 O6 0.80182 (8) 0.81238 (8) 0.35415 (17) 0.0089 (2)
O7 O7 0.71481 (8) 0.71419 (8) 0.05039 (16) 0.0086 (2)
O8 O8 0.79017 (8) 0.72936 (8) −0.31139 (16) 0.0097 (2)
B B 0.88991 (10) 0.77981 (19) 0.6753 (4) 0.0076 (4)
H3 H3 0.735 (2) 0.8677 (12) 0.732 (5) 0.21 (2)*
* Isotropic displacement parameter (Å2
). **Fixed according to EMPA analyses.
492
493
24
TABLE 13. ANISOTROPIC DISPLACEMENT PARAMETERS (Å2
) FOR OXY-SCHORL FROM494
PŘIBYSLAVICE495
496
Site U11 U22 U33 U12 U13 U23
X 0.0267 (13) 0.0267 (13) 0.0263 (18) 0.0134 (7) 0 0
Y 0.0087 (2) 0.00611 (15) 0.0121 (2) 0.00433 (10) −0.00216 (15) −0.00108 (7)
Z 0.0062 (2) 0.0058 (2) 0.0058 (2) 0.00309 (18) 0.00034 (15) −0.00008 (16)
T 0.0054 (2) 0.00520 (19) 0.0064 (2) 0.00266 (15) −0.00021 (15) −0.00044 (14)
O1 0.0494 (15) 0.0494 (15) 0.0102 (15) 0.0247 (8) 0 0
O2 0.0207 (7) 0.0069 (7) 0.0132 (8) 0.0035 (4) 0.0004 (3) 0.0008 (6)
O3 0.0213 (9) 0.0123 (6) 0.0063 (7) 0.0107 (4) 0.0007 (6) 0.0004 (3)
O4 0.0145 (8) 0.0074 (5) 0.0114 (8) 0.0072 (4) 0.0011 (6) 0.0006 (3)
O5 0.0149 (8) 0.0082 (5) 0.0105 (7) 0.0075 (4) 0.0012 (6) 0.0006 (3)
O6 0.0090 (5) 0.0103 (5) 0.0070 (5) 0.0047 (4) −0.0003 (4) −0.0009 (4)
O7 0.0088 (5) 0.0068 (5) 0.0082 (5) 0.0024 (4) −0.0009 (4) −0.0008 (4)
O8 0.0075 (5) 0.0115 (5) 0.0111 (5) 0.0054 (5) 0.0010 (4) 0.0021 (4)
B 0.0077 (7) 0.0074 (10) 0.0074 (10) 0.0037 (5) 0.0000 (4) 0.0000 (8)
497
TABLE 14. SELECTED BOND LENGTHS FOR OXY-SCHORL FROM PŘIBYSLAVICE498
499
Site Anion Distance s.d. Site Anion Distance s.d.
X O2i
2.519 (3) Z O6xiii
1.8615 (13)
O2ii
2.519 (3) O7 1.8804 (12)
O2iii
2.519 (3) O8 1.8857 (12)
O4iv
2.772 (2) O8xiv
1.9264 (12)
O4v
2.772 (2) O7xv
1.9589 (12)
O4vi
2.772 (2) O3xiii
1.9814 (9)
O5vii
2.821 (2) avg. 1.916
O5viii
2.821 (2)
O5ix
2.821 (2) T O6 1.6108 (13)
avg. 2.704 O7 1.6149 (11)
O5xvi
1.6253 (7)
Y O2 1.9941 (12) O4 1.638 (8)
O2x
1.9942 (12) 1.622
O6xi
2.0387 (13)
O6 2.0387 (13) B O2 1.357 (3)
O1xii
2.052 (2) O8viii
1.3841 (18)
O3 2.1572 (19) O8xvii
1.3841 (18)
avg. 2.046 avg. 1.375
Symmetry codes: (i) x−1, y−1, z; (ii) −x+y, −x+1, z; (iii) −y+1, x−y, z; (iv) −x+y, −x+1, z+1;
(v) x−1, y−1, z+1; (vi) −y+1, x−y, z+1; (vii) −y, x−y, z+1; (viii) x, y, z+1; (ix) −x+y, −x, z+1;
(x) −x+y+1, −x+2, z; (xi) x, x−y+1, z; (xii) x+1, y+1, z; (xiii) −x+y+2/3, −x+4/3, z−2/3; (xiv)
−x+y+2/3, −x+4/3, z+1/3; (xv) −y+4/3, x−y+2/3, z−1/3; (xvi) −x+y+1, −x+1, z; (xvii)
−x+y+1, y, z+1.
25
TABLE 15. BOND VALENCE TABLE FOR OXY-SCHORL FROM PŘIBYSLAVICE500
501
X Y Z B T ∑
O1* 0.363 1.088
O2 0.091 0.466 1.039 2.063
0.091 0.466
0.091
O3* 0.298 0.411 1.119
O4 0.046 0.965 1.975
0.046
0.046
O5 0.040 0.997 2.033
0.040
0.040
O6 0.415 0.571 1.033 2.020
0.415
O7 0.545 1.021 2.005
0.439
O8 0.535 0.964 1.978
0.480 0.964
∑ 0.531 2.423 2.980 2.966 4.015
IC(avg) 0.632 2.400 2.968 3.000 3.991
Δ 0.101 -0.024 -0.012 0.034 -0.025
IC(avg) = average ionic charge of atoms occupying the site. *Hydrogen bond donor.
502
503