A possible new mineral species ferrogate

(1)

A POSSIBLE NEW MINERAL SPECIES, “FERROGATEHOUSEITE”

(Fe,Mg) (PO ) (OH) FROM CONT

₅

_{4 2}

₄

U PEGMATITE, ROMÂNIA

1

2

1

2 N. CALIN , A-M. FRANSOLET , M. BAIJOT , S. MARINCEA , D-G. DUMITRAS , F. HATERT ,

1

1 M.A. ANASON , A.M. IANCU

Phosphates belonging to the triphylite - lithiophilite series

generally occur as nests in the spodumene and feldspar

masses. They from granular masses of greenish gray

color that turns locally into dark or black, due to the

weathering. Both optical and scanning electron microscope

studies show that triphylite abundantly contains inclusions

of wolfeite and of a gatehouseite - like phase, the later

occurring

on

the (001) perfect cleavage plane of triphylite.

X-ray powder data were obtained on a representative sample

and indexed according to ICDD file 01-070-0516, belonging

to gatehouseite. These data allow the refinement of the

unit-cell parameters, in the space group P2 2 2 (19)

₁ ₁ ₁

.

The

refined parameters are:

a = 9.103(3)

Å

, b = 18.019(6)

Å

and

c = 5.685(9)

Å

.

The a and b parameters are slightly larger

while c is slightly smaller

compared to those of gatehouseite,

given by Pring and Birch

(1993), i.e., a = 9.097(2)

Å

,

b = 18.002(3)

Å

and c = 5.693(2)

Å

.

Table 1. Unit-cell parameters for triphylite

Table 2. Representative electron-microprobe

analysis of triphylite

Table 3. Unit-cell parameters for ferrisicklerite

Table 4. Representative electron-microprobe

analysis of ferrisicklerite

Table 5. Unit-cell parameter for heterosite

Table 6. Representative electron-microprobe

analysis of heterosite

Tab

le

7. Unit-cell parameters for gatehouseite

Table 9. Representative electron-microprobe analysis of ferrogatehouseite

Table 8. Chemical structural formulas of

ferrogatehouseite

Photomicrograph of ferrisicklerite in

association with feldspars. Plane polarized

light. Crossed nicols.

To achive this the goals of this work, a series of analytical

methods were used as follows:(1)optical study with Leica and

Jenapol-U polarizing microscopes; (2) X-ray powder diffraction

using a Bruker D8 Advance diffractometer (Ni-filtred Cu Ka

radiation,



= 1.54060Å, accelerating voltage 40 Kv, beam

current 40 mA); (3) electron-microprobe analyses, using

CAMECA SX 50 device in wavelength-dispersive mode.

ferrisicklerite

fe

rri

sic

kle

rit

_e

albite

B

ack-scattered image

of ferrogatehouseite in triphylite.

“ferrogatehouseite”

triphylite

Photomicrograph of ferrogatehouseite

( 30 µm in length, 20µm in width) on cleavage .

triphylite

“ferrogatehouseite”

This research was supported by the Executive Agency for Higer Education, Research,

Development and inovation Funding (UEFISCDI), Ministry of National Education in Romania,

through the projects IDEI PN-II-ID-PCE-2013-3-0023 and ERA-MIN PT 339, 25.03.2014.

720

1. Department INI, Geological Institute of Romania, 1 Caransebes Str. , RO-012271, Bucharest, Romania,

[email protected]

2. Université de Liège, Laboratoire de Minéralogie, B18, Sart Tilman, 4000, Belgique.

Geological map of Romania

0

50 _100Km

1 =

schists and muscovite-bearing gneisses

;

2 =

kyanite schists

; 3 =

staurolit schists

;

4 =

garnet-bearing schists

;

5 =

a

m

ph

ibolite

s

,

gneisses

and schist

s

;

6 = pegmatite

s quartzo-feldspathic

;

7 =

albite and spodumene-bearing pegmatites

;

8 = graphic

pegmatites.

phosphate

muscovite

quartz

feldspar

muscovite

phosphate

albite

phosphate

quartz

albite

muscovite

feldspar

muscovite

phosphate

quartz

Hand specimens of pegmatites from Contu

ferrisicklerite

fe

rri

sic

kle

rit

_e

albite

_albite

Photomicrograph of triphylite sample with inclusion of

ferrogatehouseite. Plane polarized light. Crossed nicols.

ferrogatehouseite

triphylite

ferrogatehouseite

Photomicrograph showing the association ferrisicklerite - heterosite - quartz.

Heterosite has an obvious pleochroism in tints of mauve and yellow, whereas ferrisicklerite has more

evident pleochroism in tents.

ferrisicklerite

heterosite

ferrisicklerite

heterosite

quartz

Gatehouseite, Mn

₅

(PO

₄

)

₂

(OH)

₄

,

is a rare Mn-bearing

phosphate, since this mineral is only reported in a

sedimentary iron ore deposit in Australia (Pring and

Birch, 1993). Like in many Mn-bearing phosphates

structures, Fe may replace Mn and a complete solid

solution often exists between the Mn- and Fe-bearing

end-members. One more time, our work leads us to

consider the existence of an hypothetic new species,

“ferrogatehouseite”, which would be the iron

dominant equivalent species of gatehouseite.

During the research on the Li-bearing pegmatites from

Contu (Cibin Mountains, South Carpathians, Romania) a

rich phosphate association, including heterosite –

purpurite, lithiophilite – triphylite, sicklerite –

ferrisicklerite, fluorapatite, vivianite, monazite, wolfeite

was identified. Other associated minerals include

spodumene, quartz, muscovite, K-feldspar, plagioclase,

beryl, cassiterite, columbite group minerals, lepidolite,

rutile, scarce schorl, uraninite, topaz, spessartine,

sillimanite, titanite. Pegmatites from Contu are hosted

by micaschists and gneisses related to the Sebes - Lotru

Series.

Electron-microprobe analyses of this mineral, identified as iron-rich

gatehouseite (sample 14/c4), yielded (in wt.% oxides): P

₂

O

₅

= 26.76, FeO

= 38.97, MnO = 27.15, MgO = 0.41, CaO = 0.05, H

₂

O (calculated for charge

balance) = 6.79, total =100.13. The crystal-chemical formula which

results from this composition is: (Fe

_2.877

Mn

_2.030

Mg

_0.053

Ca

_0.004

)(PO

₄

)

₂

(OH)

₄

,

which is related to the one of gatehouseite but with Fe > Mn. Chemical

analyses on two other samples yielded similar empiric formulae, i.e.,

(Fe

_3.083

Mn

_1.855

Mg

_0.021

Ca

_0.009

)(PO

₄

)

₂

(OH)

₄

and (Fe

_2.735

Mn

_1.717

Mg

_0.042

Ca

_0.003

)

(PO

₄

)

₂

(OH)

₄

(samples 13/c4 and 17/c4, respectively).

Further investigations by FTIR and micro-Raman are needed to acquire

more details about the H

₂

O content of this potential ferrous homologue

of gatehouseite. The petrographic texture indicates that

“ferrogatehouseite” as well as wolfeite, partially replaced triphylite

along its cleavage plane during the hydrothermal stage.

Acknowledgements

A

NDERSSON

, A. S., K

ALSKA

, B., H

ÄGGSTRÖM

, L. and T

HOMAS

, J. O. (2000): Lithium extraction/insertion in LiFePO

₄

:

An X – ray diffraction and Mössbauer spectroscopy study. Solid State Ionics, 130, 41 – 52.

L

OSEY

, A., R

AKOVAN

, J. and H

UGHES

, J. M., F

RANCIS

, C. A., D

YAR

, M. D. (2004): Structural variation in the

lithiophilite – triphylite series and other olivine group structures. The Canadian Mineralogist, Vol. 42, pp.

1105 – 1115.

P

RING

, A.,

AND

B

IRCH

, W. D. (1993): Gatehouseite, a new manganese hydroxy phosphate from Iron Monarch,

South Australia. Mineral. Mag., 57, 309 – 313.

S

ABAU

, G., I

LINCA

, G., M

ARINCEA

, S., R

OBU

, L. (1990): Evaluation of the lithium potential of the Romanian

pegmatites and of the possibilities of use. I. South Carpathians (Cibin Mountains). Unpubl. Report,

Geological Institute of Romania, 65 pp.

References:

IGR

1906

Sample

a(Å)

b(Å)

c(Å)

N 113

5.841(9) 9.765(5)

4.765(4)

N 107 b

5.829(2) 9.749(4)

4.773(6)

29 B

5.837(4) 9.757(8)

4.768(9)

N 109

5.835(3) 9.756(6)

4.770(3)

N 114 A

5.824(3) 9.748(1)

4.777(2)

N 128

5.833(6) 9.718(7)

4.772(3)

Ci_1d

5.810(5) 9.758(3)

4.783(6)

Ce. 1C

5.810(4) 9.742(4)

4.773(2)

Ce. 2D

5.844(5) 9.778(6)

4.773(2)

N 129

5.857(1) 9.811(9)

4.776(2)

N 122

5.824(9) 9.775(2)

4.773(6)

N 120

5.821(3) 9.763(1)

4.782(8)

Mean

5.830(5)

9.76(5)

4.774(4)

Sample

a(Å)

b(Å)

c(Å)

23C1

4,719(1)

10,368(6)

6,035(5)

65CI

4,718(4)

10,366(3)

6,031(2)

9E

4,712(4)

10,379(6)

6,039(10)

29B

4,718(1)

10,378(3)

6,033(4)

Ci 1D

4,712(8)

10,375(7)

6,047(6)

Ci 1D1

4,713(7)

10,380(6)

6,038(7)

Mean

4,715(4)

10,374(5)

6,037(6)

Sabau et.al. (1990)

4,698(4)

10,365(5)

6,034(9)

Anderson et al. (2000) 4.6908(2) 10.3290(3) 6.0065(2)

Losey et al. (2004)

4,7138(6) 10,3826(1) 6,0499(5)

Sample

a(Å)

b(Å)

c(Å)

N 103

5,945(6) 10,076(8) 4,793(1)

Ce 59

5,941(7) 10,061(5) 4,791(8)

23C1

5,943(9) 10,056(8) 4,796(2)

N 112

5,945(4) 10,061(9) 4,797(7)

Mean

5,944(7) 10,064(8) 4,794(5)

ICDD 00-033-0802

5,946

10,063

4,793

Triphylite

9/c2

10/c2

11/c2

19/c4

20/c4

39/c12 40/c12

%

P

2

O

5

45.94

45.98

45.79

45.93

46.51

46.26

46.18 FeO

30.73

30.9

30.46

30.23

30.8

29.64

29.45 MnO

15.04

15.14

15.23

15.21

15.1

15.65

16 MgO

0.3

0.28

0.29

0.24

0.25

0.25 CaO

0.01

0.04

0.02

0.06

0.04

0.07

0.04 Li

2

O

9.66

9.62

9.64

9.70

9.70 Total 1

92.02

92.34

91.79

91.67

92.7

91.87

91.92 Total 2

101.68 102.00 101.41 101.31 102.34 101.57 101.62

Triphylite

94/c9

159/c1 160/c1 161/c1 166/c1 167/c1 171/c1

%

P

2

O

5

46.14

46.11

46.07

45.31

46.59

46.12 FeO

30.88

29.29

29.32

26.38

26.75

26.45 MnO

15.31

16.82

16.6

19.47

19.37

19.26 MgO

0.29

0.14

0.06

0.07

0.06 CaO

0.04

0.03

0.05

0.03

0.03 Li

2

O

9.69

9.68

9.69

9.68

9.51

9.79

9.69 Total 1

92.66

92.4

92.16

91.27

92.81

91.92 Total 2

102.35 102.08 102.09 101.84 100.78 102.60 101.61

Triphylite

9/c2

10/c2

11/c2

19/c4

20/c4

39/c12 40/c12

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

P

1

1 Fe

2+

0.660

0.663

0.657

0.65

0.654

0.633

0.63 Mn

0.327

0.329

0.332

0.331

0.324

0.338

0.346 Mg

0.011

0.010

0.011

0.009

0.009 Ca

0

0.001

0

0.001

0.001 Li

0.999

0.998

0.997

0.998

0.995

0.997 Triphylite

94/c9

159/c1 160/c1 161/c1 166/c1 167/c1 171/c1

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

1PO

4

P

1

1 Fe

2+

0.660

0.627

0.628

0.575

0.567

0.566 Mn

0.332

0.364

0.360

0.429

0.416

0.419 Mg

0.011

0.005

0.002

0.002 Ca

0.001

0

0.001

0

0 Li

0.998

0.997

0.998

Ferrisicklerite 42/c1 43/c1 47/c1 56/c3 57/c3 59/c3 60/c3 71/c6

% % % % % % % %

P2O5 44,67 43,95 43,28 45,14 44,54 43,98 42,87 41,79 FeO 30,00 31,03 30,17 30,69 30,94 30,9 31,68 32,11 MnO 18,83 18,78 19,61 18,36 18,49 18,73 19,36 19,72 MgO 0,10 0,11 0,1 0,1 0,11 0,11 0,11 0,11 CaO 0,52 0,37 0,66 0,28 0,29 0,36 0,46 0,53 Li2O 9,13 9,06 8,76 9,35 9,22 9,07 8,78 8,52 Total 1 94,12 94,24 93,82 94,57 94,37 94,08 94,48 94,26

total 2 103,25 103,30 102,58 103,92 103,59 103,15 103,26 102,78

Ferrisicklerite 72/c6 79/c7 81/c7 84/c10 125/c9 158/c1 174/c6 175/c6

% % % % % % % %

P2O5 45,13 43,3 44,14 44,31 42,93 45,21 43,66 42,56 FeO 30,65 31,13 30,39 30,77 30,15 29,76 29,42 30,12 MnO 18,58 18,96 18,71 18,65 19,77 17,74 19,71 20,04 MgO 0,09 0,12 0,12 0,1 0,09 0,15 0,08 0,06 CaO 0,25 0,74 0,44 0,38 0,27 0,79 0,42 0,53 Li2O 9,37 8,72 9,20 9,13 8,89 9,10 8,97 8,68 Total 1 94,7 94,25 93,8 94,21 93,21 93,65 93,29 93,31

total 2 104,07 102,97 103,00 103,34 102,10 102,75 102,26 101,99

Ferrisicklerite 42/c1 43/c1 47/c1 56/c3 57/c3 59/c3 60/c3 71/c6 PO4 PO4 PO4 PO4 PO4 PO4 PO4 PO4

P 1 1 1 1 1 1 1 1

Fe 0,663 0,697 0,688 0,671 0,687 0,693 0,729 0,758 Mn 0,421 0,427 0,453 0,406 0,415 0,426 0,451 0,472 Mg 0,003 0,004 0,003 0,003 0,004 0,004 0,004 0,004 Ca 0,014 0,010 0,019 0,007 0,008 0,010 0,013 0,015 Li 0,970 0,978 0,961 0,984 0,983 0,979 0,973 0,968

Ferrisicklerite 72/c6 79/c7 81/c7 84/c10 125/c9 158/c1 174/c6 175/c6 PO4 PO4 PO4 PO4 PO4 PO4 PO4 PO4

P 1 1 1 1 1 1 1 1

Fe 0,670 0,710 0,679 0,685 0,693 0,650 0,665 0,699 Mn 0,411 0,438 0,424 0,421 0,460 0,392 0,451 0,471 Mg 0,003 0,004 0,004 0,003 0,003 0,005 0,003 0,002 Ca 0,006 0,021 0,004 0,010 0,007 0,021 0,012 0,015 Li 0,986 0,957 0,990 0,978 0,984 0,956 0,975 0,968

Heterosite 44/c1 45/c1 48/c1 58/c3 61/c3 62/c3 63/c3

% % % % % % %

P2O5 46,65 45,42 46,75 46,85 46,87 46,79 47,19 Fe2O3 33,09 33,16 31,95 32,70 32,76 33,47 33,17 Mn2O3 20,33 20,58 19,99 19,90 20,018 19,38 20,10 MgO 0,11 0,08 0,12 0,11 0,07 0,10 0,07 CaO 0,23 0,33 0,38 0,28 0,23 0,35 0,18 Total 100,41 99,578 99,19 99,85 99,95 100,09 100,72

Heterosite 64/c3 65/c3 70/c6 74/c7 75/c7 76/c7 77/c7

% % % % % % %

P2O5 47 46,14 46,25 47,08 47,42 46,21 47,69 Fe2O3 33,18 33,16 32,69 32,24 32,72 32,26 33,15 Mn2O3 19,70 20,60 19,52 19,49 19,50 19,18 19,57 MgO 0,08 0,06 0,1 0,09 0,09 0,08 0,09 CaO 0,17 0,27 0,53 0,59 0,42 0,52 0,16 Total 100,14 100,24 99,10 99,49 100,16 98,25 100,66

Heterosite 78/c7 80/c7 83/c10 149/c1 153/c1

% % % % %

P2O5 47,17 47,22 46,27 44,95 45,63 Fe2O3 32,58 33,36 34,61 31,49 32,35 Mn2O3 19,38 19,85 19,72 19,55 18,90 MgO 0,09 0,09 0,09 0,14 0,12 CaO 0,29 0,14 0,14 2,01 0,58 Total 99,51 100,66 100,84 98,14 97,58

Heterosite 44/c1 45/c1 48/c1 58/c3 61/c3 62/c3 63/c3 1PO4 1PO4 1PO4 1PO4 1PO4 1PO4 1PO4

P 1 1 1 1 1 1 1

Fe3+ 0,630 0,649 0,607 0,620 0,595 0,635 0,624 Mn3+ 0,391 0,407 0,384 0,381 0,368 0,372 0,383 Mg 0,004 0,003 0,004 0,004 0,002 0,003 0,002 Ca 0,006 0,009 0,010 0,007 0,005 0,009 0,004

Heterosite 64/c3 65/c3 70/c6 74/c7 75/c7 76/c7 77/c7 1PO4 1PO4 1PO4 1PO4 1PO4 1PO4 1PO4

P 1 1 1 1 1 1 1

Fe3+ 0,627 0,638 0,628 0,608 0,613 0,620 0,617 Mn3+ 0,377 0,401 0,379 0,372 0,369 0,373 0,368 Mg 0,003 0,002 0,003 0,003 0,003 0,003 0,003 Ca 0,004 0,007 0,014 0,015 0,011 0,014 0,004

Heterosite 78/c7 80/c7 83/c10 149/c1 153/c1 1PO4 1PO4 1PO4 1PO4 1PO4

P 1 1 1 1 1

Fe3+ 0,614 0,627 0,665 0,622 0,630

Sample

a(Å)

b(Å)

c(Å)

23 C1

9,100(7) 17,992(9) 5,702(8)

10 C

9,098(3) 18,017(3) 5,688(2)

Ci 58 F

9,103(3) 18,019(6) 5,685(9)

ICDD 01-070-0516

9,110

18,032

5,692

Pring and Birch (1993) 9,097(2)

18,002

5,693(2)

13/c4

Ca

0,009

(Fe

3,083

Mn

1,855

Mg

0,021

)

4,959

(PO

4

)

2

(OH)

4

14/c4

Ca

0,004

(Fe

2,877

Mn

2,030

Mg

0,053

)

4,960

(PO

4

)

2

(OH)

4

15/c4

(Fe

2,793

Mn

2,117

Mg

0,055

)

4,965

(PO

4

)

2

(OH)

4

16/c4

Ca

0,0018

(Fe

2,9631

Mn

1,9575

Mg

0,0355

)

4,9562

(PO

4

)

2

(OH)

4

17/c4

Ca

0,0034

(Fe

2,7353

Mn

1,7171

Mg

0,0424

)

4,4949

(PO

4

)

2

(OH)

4

18/c4

(Fe

2,9897

Mn

1,9335

Mg

0,0237

)

4,9470

(PO

4

)

2

(OH)

4

120/c6 Ca

0,0047

(Fe

3,7168

Mn

1,2523

Mg

0,0265

)

4,9956

(PO

4

)

2

(OH)

4

121/c6 Ca

0,0028

(Fe

3,6019

Mn

1,3550

Mg

0,0247

)

4,9818

(PO

4

)

2

(OH)

4

122/c6 Ca

0,0009

(Fe

3,5570

Mn

1,3776

Mg

0,0382

)

4,9730

(PO

4

)

2

(OH)

4

124/c6 Ca

0,0018

(Fe

3,5819

Mn

1,3569

Mg

0,0250

)

4,9640

(PO

4

)

2

(OH)

4

(FeMn)

5

(PO

4

)

2

(OH)

4

13/c4

14/c4

15/c4

16/c4

17/c4

18/c4

120/c6

121/c6

122/c6

124/c6

%

P

2

O

5

26,6

26,76

26,81

26,73

29,05

26,69

26,54

26,58

26,71

26,69

FeO

41,51

38,97

37,91

40,09

40,22

40,39

49,93

48,46

48,09

48,39

MnO

24,66

27,15

28,37

26,15

24,93

25,79

16,61

18 18,39

18,1

MgO

0,16

0,41

0,42

0,27

0,35

0,18

0,2

0,187

0,29

0,19

CaO

0,1

0,05

0 0,02

0,04

0 0,05

0,03

0,01

0,02

H

2

O

6,75

6,79

6,80

6,78

7,37

6,77

6,73

6,74

6,77

Total 1

93,03

93,34

93,51

93,26

94,59

93,05

93,33

93,26

93,49

93,39

total 2

99,78

100,13

100,31

100,04

101,96

99,82

100,06

100,00

100,27

100,16

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

2PO

4

P

2

2 Fe

3,083

2,877

2,793

2,963

2,735

2,989

3,716

3,601

3,557

3,581

Mn

1,855

2,030

2,117

1,957

1,717

1,933

1,252

1,355

1,377

1,356

Mg

0,021

0,053

0,055

0,035

0,042

0,023

0,026

0,024

0,038

0,025

Ca

0,009

0,004

0 0,001

0,003

0 0,004

0,002

0,000

0,001