American Mineralogist, Volume 67, pages 536-544, 1982
Fluorine end-membermicas and amphibolesl
E. U. PETnnsEN,
E. J. Esseue, D. R. PBecon
Department of Geological Sciences
The University of Michigan
Ann Arbor, Michigan 48109
eNo J. W. Velley
Department of Geology
Rice University
Houston, Texas 77001
Abstract
The near end-memberminerals fluorphlogopite (xF = 0.96) and fluortremolite (xF :
0'82) have been found in Grenville marbles near Balmat, New York. These micas and
amphiboles,like other fluorine-rich mineralsreported in the literature, are extremely low in
iron. The substitution of F for OH is partly responsiblefor stabilizing these minerals in the
granulite facies marbles of the Adirondacks. Fluorine-rich amphibolesand micas are more
common than generally recognized. A literature review shows that many amphiboles and
micas have more than fifty percent of the interlayer site occupied by fluorine. This degree
of solid solution qualifies thesephasesas independentminerals, but they are not currently
recognized by the I.M.A. We propose that fluorbiotite, fluorphlogopite, fluoractinolite,
fluorarfvedsonite, fluoredenite, fluorhastingsite, fluorpargasite, fluorrichterite, fluorriebeckite, fluortremolite, fluoredenitic hornblende, fluorhastingsitichornblende, fluorpargasitic hornblende, fluortremolitic hornblende,fluorferro-edenite,and fluormagnesio-arfvedsonite be formally applied as mineral names for these phases. Identification of the
mineralogically and petrologically important solid solution of fluorine for hydroxyl is
currently obscured by use of namesthat imply hydroxyl end-members.
Introduction
In this paper we describe the occurrence of the
near end-member minerals fluorphlogopite 1Xp :
0.96)where XF : F/(F+OH+O) and fluortremolite
(XF : 0.82) found in Grenville marbles near Balmat, New York. These phlogopitesand tremolites
are by far the most fluorine-rich that have been
reported. The solid solution of fluorine is important
in stabilizing micas and amphibolesin the amphibolite to granulite facies marbles of the Adirondacks
(Valley and Essene,1980;Valley et at., l98Z).
The fluorphlogopite and fluortremolite were identified by routine electron microprobe analyses of
hydrous minerals in silicious marbles. Although
vast amounts of chemical data on micas and amphiboles have been produced with the electron microprobe, most analyseshave not included fluorine
I Contribution No.
372 from the Mineralogical Laboratory,
The University of Michigan, Ann Arbor, Michigan 48109.
0003-004)v82l0506-4538$02.00
becauseof the relative difficulty of analysis.Recent
advancesin crystal spectrometerdesign and operation (curved TAP analyzer crystal, ultra-thin detector windows and a high operatingvacuum) allow for
routine fluorine analysis by microprobe, although
longer counting periods are still required and fluorine is not accessibleby most energy dispersive
systems.Since many hydroxyl-bearingsilicatesefficiently scavenge fluorine from aqueous fluids, a
complete chemical analysis should include fluorine.
Fluorine-rich micas and amphibolesmay be more
common than is generally recognized.An examination of the literature to determine the extent of
fluorine substitution (e.9., Doelter, 1912, 1914,
l9l7; Hintze, 1904, 1933;Deer et al., 1962,1963;
Leake, 1968;Kearns et al., 1980)has revealed 17
micas and amphiboles (Tables 1 and 2) which have
XF : F/(F+OH+O) > 0.5 and many others have
more fluorine than any other interlayer anion. Some
minerals which could have fluorine were not ana-
538
539
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
Table l. Indices of refraction, 2V" extinction angle and unit cell
constants of fluorphlogopite, fluortremolite and norbergite
phlogopite
BHT-1
Fluorphlogopite
Fluortremlite
cov 5o-2'
Bt[r-1
Norbergit€
B]fr-l
L.522(2)
r.536<2)
1.587(2)
1.s88(2)
B
1.548(2)
1.553(2)
7.599(2)
r.563(2)
Y
r.s49(2)
L.546(2)
1.608(2)
L.582(2)
Y-4
0.027(3)
0.027(3)
0.021(3)
0.024(3)
4 7( 5 )
2Vz (reas)
1 s( s )
e(5)
8 s( 5 )
cAz
88(5)
87(5)
22(s)
.(l)
r (it
(l)
"
B
s.302(7)
5.303(6)
9.19(1)
9.210(8)
ce1l vol. (43)
10.r.39(9)
1oo" 12'(6) 99"5s'(6)
485,6(9)
487.8(8)
10.126(9)
9.836(s) 10.259(9)
1 8 . 0 2( 1 )
5 . 2 6 7( 9 )
8,747(8)
(tt'
4.7O1
Fluorphlogopite
Crystals of fluorphlogopite that have been dissolved out of their calcite matrix are shown in
Figure lb. The grain size varies from 0.1 mm to 2
mm; the larger grains are generally subhedral and
gemmy, showing little evidenceof their basal cleavage unless they are crushed; the smaller grains are
all euhedral. The phlogopite is colorlessboth in thin
section and in hand specimen. The appearanceof
this fluorphlogopite is similar to that of other ironpoor, hydroxyl-rich phlogopitesin Adirondack marbles (Valley and Essene,1980)and doesnot appear
to bear any special relation to fluorine content.
ro4' 40'(6)
902(r)
422.4(4)
Lvalle! eL aL. (7981) (xF = 0.57)
lyzed for fluorine. Since the high fluorine content
(XF>0.5) allows thesemineralsto be consideredas
distinct minerals, the authors were surprised to
learn that no fluorine end-membermicas or amphiboles are currently listed as minerals by Fleischer
(1980)or recognizedby the I.M.A. Commissionon
New Minerals and Minerals Names, although some
of the nameshave becomefamiliar through informal
usage.Dr. Max Hey, vice-chairmanof the I.M.A.
Commission, has expressedthe opinion (written
communication, 1980)that no ruling by the commission is necessaryand that names such as fluorphlogopite and fluortremolite, etc. are appropriate for
these minerals.
Table 2. Electron microprobe analysis in oxide weight percent
fluorphlosopite
and normalized about
"":Tlrr$S#[temolite,
F phlog
F treo
No rb
BIfI-1
BMT-1
BMT-1
44.34
:0.05
59.30
:0.05
29.74
Tio2
d"o r
rr,4 7
0,26
0.10
so.05
0.00
0.07
0.00
s0.05
0.00
<0.05
:0.05
:o.os
s0. 05
sio 2
Fe ,0.
*
Fe0*
lrnO
24.58
Mgo
0 . 07
12.o3
u-4i
2.O7
ild
nd
Kzo
r0.44
0,6r
BaO
r.58
s0.05
o.25
ad
0.40
0.50
0.36
I
8 , 53
3.84
17.86
CI
0.05
s0.02
so.o2
100.94
).0L,47
101.55
swr
Associationsand mineralogy
Geology
Fluorine-rich micas and amphibolesoccur in siliceous marbles which are common in the N.W.
Adirondack Lowlands (Engel and Engel, 1953).
These marbles were metamorphosedto upper amphibolite facies (Buddington,1939)during the Grenville Orogeny. Recent estimatesyield 6.5-t-1kbar
and 650130oC for the peak of metamorphism at
Balmat (Brown et al., 1978;Bohlen et al., 1980).
The minerals described in this report (in sample
BMT-I) were collected on the 900-foot level of the
Balmat No. 3 Mine (Lower Gleason Orebody).
Associated with fluorphlogopite and fluortremolite
are norbergite, calcite and minor graphite, pyrite,
fluorapatite, and sphalerite (Fig. 1a).
0 .1 7
CaO
N a2 o
nd
0.41
S1
3.745
8,010
1.000
A-1
0,855
0.000
0.000
0,104
0.041
s0.005
T1
<0,005
s0.005
0.006
0.000
0.000
0.000
0.004
-<0.003
3.003
s0.005
s0.005
s.005
2.89L
4.948
2,990
0.005
1.74t
Na
0.061
0.543
0.006
4d
K
o.945
0.105
nd
Ba
0,0r0
s0.005
nd
F
1.9L4
1.638
r . 8 97
oil*
0.084
0.352
c1
0,002
0.005
0.091
nd.
nd
nd
o.orz*
0.96
0.82
h
Mg
o
r'l (F + oE) "
*alculated:
trueing
**reaswed;
caleulated
ualues;
laLjueted
nd-rct
0,96
fo" ?, CL, 0R, Fezx;
dptemined.
540
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
phlogopites(Valley and Essene, 1980).The nearly
complete absence of iron in these samples makes
the fluorescence possible, and it should be anticipated that other nearly iron-free phlogopites will
also fluoresce.
Fluortremolite
Fig. l. (a) Photomicrographof BMT-I, (b) Single crystals of
fluorphlogopite (bar scale : 100 rr).
Refractive indices were determined in oils on a
singlecrystal mountedon a spindlestage(Table 1).
The 2V was estimated from acute bisectrix figures
using Tobi's (1956) method. Lattice parameters
were measuredfrom X-ray diffraction photographs
taken in vacuo with a 360 mm circumference Gandolfi camera. A least-squaresrefinement for the
measured reflections yielded the parameters given
in Table 1 Precessionphotographs show a single
crystal of fluorphlogopite (.03 mm in diameter)to be
a well-ordered lM mica with space group C2lm.
This agrees with resrrlts for other natural and synthetic fluorphlogopites (Hazen and Burnham, 1973;
McCauley et al., 1973) that are also C2lm, lM
micas.
Adirondack fluorphlogopltes fluoresce under
long (3650A) and short (25404) wavelengthultraviolet (UV) light. This property first drew attention to
the Balmat samplesundergroundin mine workings.
Fluorescent color varies with the energy of the
exciting radiation. Long-wavelength UV causes
pale green fluorescence, contrasting with a pale
blue cathodoluminescencereported for iron-poor
Fluortremolite crystals are gemmy and colorless
both in thin-section and in hand specimen.The
crystals have a fibrous habit and range in length
from 0.2 mm to 15 mm. Some fluortremolitesfluoresce pale blue in long-wavelength UV light and
bright blue under short-wavelength radiation. Orange-fluorescingand non-fluorescing varieties also
occur in the Balmat area. Fluorescence does not
appear to be related to fluorine content, but it is not
found with specimens which have even small
amounts of iron. The refractive indices and lattice
parametersfor one fluortremolite are given in Table
1. The 2V and cAZ angles were measured with a
universal-stage using hemispheres with refractive
index equal to 1.65and making no tilt corrections.
Interpolation of the measuredrefractive indices for
this fluortremolite between the values for endmember hydroxytremolite (Stemple and Brindley,
1960)and endmember synthetic fluortremolite (Comeforo and Kohn, 1954)result in an inferred composition which closely matchesthe chemical analyses (Table 2).
Norbergite
Norbergite is a widespreadmineral in the Balmat
mines. It occurs as disseminatedanhedral grains
about 1.0 mm in diameter in the purer calcitic
marble units, but it may attain a modal abundance
of 30Voas in sample BMT-I. Balmat norbergite
fluoresces a brilliant canary yellow only under
short-wave UV light which makes it extremely easy
to identify in the field. Unlike most norbergitesthis
material is white and would be difficult to distinguish in hand specimenfrom scapolite,feldspars,
barite or other white minerals if it were not fluorescent. The refractive indices and lattice parameters
are given in Table 1. The 2V was measured on a
universal-stage in a manner similar to that for
tremolite. These data are similar to those given by
Gibbs and Ribbe (1969)for a Franklin, New Jersey
norbergite.
Chemical analyses
Fluorphlogopite, fluortremolite and norbergite
were analyzed for 12 major and minor elementsby
541
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
electron microprobe using wavelength dispersive
analyzer crystals (Table 2) in the University of
Michigan microbeam laboratory. A TAP analyzer
crystal was used for light elements including fluorine. Analytical and normalization procedures for
the amphibole and mica are describedby Valley and
Essene(1980).Norbergite was normalizedaccording to the method of Gibbs and Ribbe (1969).
Because total iron amounted to less than 0.07
weight percent (calculated as FeO) in these minerals, the ferric/ferrous ratio was not determined
directly, but was inferred from normalization about
cations (see Valley and Essene,1980).Normalization about cations for other Adirondack samples
indicates that metamorphic phlogopite contains
mainly ferrous iron (van den Berg, 1975;Valley and
Essene,1980).
Hydrogen was directly determined in some samples using the extraction lines at the University of
Utah stable isotope laboratory. Between 50 and 100
mg of mineral separatewere thermally decomposed
invacuo at 1500"Cand evolvedgaseswere converted to H2 by reaction with uranium at 700"C. Contaminants were condensedwith a liquid N2 trap and
H2 was measured manumetrically. The calculated
values for H2O agreewell with the measuredvalues
(Table 2).
Table 3. Hydroxyl-site occupancies of published fluormica
analyses
5--lss--Is-
698
3,84
3.05
2.18
,82
.65
,49
.18
.35
.35
.00
.00
.19
96
o.9o
2.48
.55
.18
.26
5
0.99
2,6r
.51
.43
.00+
A
w
10
1.00
0.99
0,88
4.60
2.30
2.r4
1.00
.50
.48
.00
,50
,29
.00
,00
.23
A1
15
0.00
0.00
3.31
2,58
.80
.59
.20
.47
.00
.00
7
10
8
I
8
11
A14
A8
Af?
0.00
o,4a
0.01
0.03
0.oo
2.95
2.76
2.48
2.33
2.20
.50
.59
.52
,50
.51
.40
.41
,48
.50
.49
.00
.00
'00+
.00+
.00
11
12
13
o
rr
o.99
0.90
o.54
3 60
2.59
2.40
.78
.58
.58
.22
.15
.r2
.00
.27
.30
4
L6
15
0.94
0.79
2.45
2.L9
.55
.51
.45
.49
.00+
.00+
96-4
0.44
2-90
.71
.29
.oGr
3.05
2,80
2.78
2.38
2.29
.70
.62
.62
.5:7
.52
.17
.19
.25
.43
.25
I
2
fluortrenollte
fluoractlnolite
hornblende
f luortr@olltlc
5
fluorrlchterlte
7
I
fluorrlebecklte
fluorarfvedsonlte
f luomagnes
lo-arf
F1
I
!,^rn.Ydra
f luorf
vedsoni!e
ia
pargaslte
erroan
homblende
f luorpargasltlc
3
3
3
fluorf
erroan
Darsasltic
homblende
fluoredenlte
fluorferro-edlnlte
f luoredenitlc
F1,r^?hqerJnoel
hornblende
ra
Nomenclatureof other fluorine-rich minerals
In view of the importance of fluorine substitution
in micas and amphiboles(Valley and Essene,1980;
Valley et al., 1981),we recommendthat fluor be
added as a prefix to mineral namesfor mineralswith
greater than 50Vo fluorine in the interlayer site.
These should be regardedas official mineral names
rather than as modiflers as recommendedby Leake
and the I.M.A. Subcommittee on Amphiboles
(1978) because these qualify as distinct minerals
(Hey, 1980,written communication).In particular
fluorphlogopite, fluorbiotite, fluorrichterite, fluortremolite, fluoractinolite, fluoredenite, fluorferroedenite, fluorhornblende, fluorriebeckite, fluorhastfluorpargasite, fluorarfvedsonite,
ingsite,
fluormagnesio-arfvedsonite, fluoredenitic hornblende, fluorhastingsitic hornblende, fluorpargasitic
hornblende, and fluortremolitic hornblendeall qualify as mineral names (Tables 3 and 4). This nomenclature, without a separatinghyphen, is chosen by
analogy with the apatite group.
Original descriptions of other amphiboles and
micas including eckermannite, lepidolite, polylitionite and zinwaldite are applied to type specimens
ill '
1,00
1.00
0.93
Rer' No' \'
Nde*
Mlneral
f luormagneslan
has rlngsite
f luomagneslo-hastlngslte
f luorhasttngsttlc
hornblende
as 2 - F;
0.70
0.98
0.98
0.90
O.A5
.19
.o0+
.23
89-21 0.42
0.68
479
3.O
1,82
.73
.44
.27
.2r
,00+
.35
4
L6
3
8
22
223
0. 86
0.94
0,96
2.60
2.76
1.90
.59
.54
.42
.4r
.46
.33
.00+
,00
.25
L7
A25
0.02
3.84
.98
.O2
,oGr
3
13
3
272
164
383
o . 9 7 3,09
0 . 9 1 2.86
0.68 1.82
.69
.66
.44
.27
.34
.32
.10
,00+
.24
u
t1
A28
A29
0.13
o.z2
2.06
1.94
,50
.50
.50
.47
.00
.03
17
A3O
0.34
1,84
.46
.43
.11
3
1011
o.84
2.65
.60
.40
.00
I7
L24
0.11
3.02
.79
.2r
.00+
3
379
o.7t
2.06
.49
26
.25
o.89
2.69
,60
.2L
,16
1 0 ULrych (1978)
1 1 uLaen et aL. tJv/dt
1 2 Admgon (1942)
1 3 Eintze (1933)
Baldzidge et aL. (1981)
1 5 Hala4ngton (1903)
Doelte" (1912, 1914, 1917)
1 7 Borley and F?ast (1983)
Thi.s paper
Petetsen (Unpbd.)
Leake (1968)
Kems et aL. (1980)
DougLas dtd PLmt (1968)
jlsen (1967.)
Dee" et aL (1966)
Bo?LeU (1963)
(19?8)
Htuth.me
oH caLeulated
492
29A
11
31A
L4
3
73
fluoreckemannlte
Bm1
folluLng
Leake (1978);
X
= Mg/(Ms + Fe)
in which XF > 0.5 (Doelter, 1912,1914, l9l7 ; Dana,
1920; Hintze, 1933; Sundius, 1945; Deer et al.,
1962;Allmann and Kortnig,1972; Bailey, 1975)and
therefore these names, sensu stricto, should really
apply to the fluorine end-members. If so, then a
hydroxyl prefix should be applied to the same
species with XOH > 0.5, and there is enough
chemical data in the literature to support the names
hydroxylepidolite, hydroxypolylithionite and hydroxy-zinnwaldite. However we prefer to ignore
original priorities and let the original namesapply to
542
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
Table 4. Hydroxyl-site occupanciesof publishedfluorphlogopite
analyses
nneral
Ref.
Nane
fluorphlogoplte
fluorbioEite
fnis paper
DoeLte! (1912, 1914, 1917)
Jacob md Ptrga-Pond.al (1932)
(1973)
Eazen and Bmh@
Rinsaite (1967)
Datu (1920)
Xn^
nib
nale
fraction
not teported
No.
\s
wtz F
\
xon
Xo
Elfll
8
68
1
7
1.00
1.00
0.99
1.00
0.88
8.53
7.63
5.14
5.85
5.70
,96
.82
,75
.65
.65
.O4
.18
.25
.35
.32
.00
r0 0
,00
.00
.00
7
6
cov-50
5
BT5
1.00
0.97
1.00
0.95
0.95
5.67
5.47
5,06
4,A2
4.61
.62
.60
.57
.54
.53
.O9
.09
.43
.46
.47
.29
.31
.00
.00
.00+
5
5
ll
13
8
7
0.99
0.91
0.7r
0.63
0.85
0.97
4.59
4,20
3.67
3.63
3.33
4.2r
. 51
.50
.49
.48
.44
.46
.28
.46
.37
.41
.39
.2t
.2L
.04
.t4
.11
.77
.33
10
1t
11,
11
10
99097
47
57
63
89-17
0.58
0.77
0.70
0.58
0.71
8. 11
.97
.86
.81
.79
.73
.03
.r4
. 19
.2t
.27
.00+
.00+
.ocr
.00+
.00+
1l
10
11
10
11
39
8A-2L
44
94-14
87
0.55
O.79
0.57
0.72
0.43
5;70
5.86
.72
.69
.69
.68
.58
.28
.3r
.31
.32
.32
.00+
.oGf
.0G|
.oGf
.00+
11
11
11
t2
12
91
43
2
I
0.68
o.52
0.58
0, 00
0.01
5.O2
4.36
.67
.55
.64
.50
.53
.33
.35
.36
.50
.47
,00+
.00f
.00+
,00*
.00*
I1
I1
2
2
66
36
773
774
0.53
0.48
0,06
0.03
.53
.52
.51
.50
.47
.48
.31
.39
.00+
.00r
. 18
.11
7.r3
6.20
5.80
4.28
valleg od. Essene (1980)
Keamee et aL, (1980)
6ePg, D@ @4 tty/t)
Baldridge , c@ichaeL
atul
Albee (1981)
1 1 G@
et aL. (1980)
1 2 Jackobson et aL. (1958)
I
I
10
0HeaLeLated@4-P
F+OH
2
Mg
hydroxyl species (as implied by Fleischer, 1980)
and to consider fluoreckermannite, fluorlepidolite,
fluorzinnwaldite, and fluorpolylithionite as the
namesfor these specieswith XF > 0.5.
Discussion
The occurrence of both fluorine and hydroxyl
micas and amphiboles leads to consideration of
possible solvi in these F/OH systems.There are
sufficient chemical data to suggestcomplete solid
solution between hydroxyl and fluorine phlogopite,
lepidolite, polylithionite, zinnwaldite, and arfvedsonite. Westrich (1981)has also synthesizedcomplete solutions in F/OH phlogopites and tremolites
at high temperatures. Although the end-member
fluoredenite(Kohn and Comeforo, 1955),fluorrichterite (Kohn and Comeforo, 1955; Gibbs et aI..
1962;Fedoseevet al., 1970;Huebner and Papike,
1970; Cameron et al., 1973),and fluormagnesioarfvedsonite (Fedoseev et al., 1970) have been
synthesizedit is not yet possibleto demonstratea
complete solid solution for these minerals because
intermediate compositons have not been reported.
The possibility of a solvus cannot be ignored, but
there is as yet no evidenceto suggesta solvusin F/
OH binary silicate systems.
The possibility of finding additional fluorine endmember silicates should be considered. In particular talc and anthophyllite which occur with tremolite at Balmat and elsewhere may eventually be
found with XF > 0.5. Only a few talc sampleshave
been analyzedfor fluorine (Rosser al., 1968;Allen,
1976;Moore and Kerrick, 1976;Rice, 1976;Mercolli, 1980) but the possibility of more significant
fluorine substitution should be considered.In some
instances (Moore and Kerrick, 1976)accurate electron microprobe analysis of talc has not been possible because proper polishing is difficult due to its
softness.Allen (1976)has analyzedtwo talcltremolite pairs from amphibolite facies Grenville marbles
in Ontario and found that fluorine partitions preferentially into the tremolite with an averagepartition
factor (XFr"/XFr.) of 0.64. Mercolli (1980) has
analyzed thirteen talc/tremolite pairs from Campolungo, Switzerland and found an average partition
factor of 0.58. If these talc/tremolite partition factors are applied to the fluortremolite in BMT-l, then
it is predicted that talc as fluorine-rich asXF : 0.50
could be found. However, such fluorine-rich talcs
may have a restricted stability, accountingfor their
apparent raity, in upper amphibolite to granulite
facies terrains. For example the reaction:
Ztalc * 3 calcite : tremolite * dolomite
(a)
+ COz + H2O
will be shifted so as to extend the stability of either
talc or tremolite dependingon the distribution coefficient for F/OH between the coexisting minerals.
For the observed talcltremolite Kp given in Mercolli (1980) the downward shift in temperature for
reaction (a) is small, indicating a slightly restricted
stability for talc. If these Kp's are representative
one may conclude that the effect of fluorine substitution on this reaction is insignificant. The results of
Slaughter et al. (1975)indicate that the assemblage
talc plus calcite is stable below 500'C and XH1O >
0.8 at 6 kbar, while Skippen (1971) proposes a
greater range in stability to slightly higher temperatures and lower XH2O but still well below 600"C.
Therefore it is likely that fluortalc will be restricted
to temperatures lower than those prevailing in the
upper amphibolite to granulite facies, which is
consistent with the absence of primary talc plus
calcite assemblagesin Adirondack samplesstudied
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
543
by Valley and Essene (1980).Fluorine-rich talcs importance of even small quantities of hydrous and
should therefore be sought in marbles from lower fluorine volatiles in partial melting.
grade metamorphic terranes.
Fluormuscovite has been reported once in an
Acknowledgments
analysis obtained over 100 years ago (Doelter,
This research was partly supported by National Science
1917). Before this is accepted as a new mineral Foundation Grant EAR 78-22568(EJE). Funds for the microspeciesthe mineral should be reanalyzedto confirm probe work were provided by the University of Michigan. Dr.
that fluorine occupies more than one half of the John R. Bowman of the University of Utah provided the water
interlayer site. There is a good chance,however, analyses. St. Joe Minerals provided accessto the Balmat mine
where BMT-l was collected. We wish to thank Robert Tracy and
that other fluormuscoviteswill be found. Kwak and Robert C. Newton for their reviews of the manuscript.
Askins (1981)report naturallyoccurringmuscovites
in which XF : 0.32. The experimentalwork of
References
Munoz and Luddington (1977)and the natural as(1942)
Eckermanite
a new alkali amphibole.
Adamson,
J.
O.
semblagesof coexisting muscovite and biotite reGeologie F<irenFrirhandlung,64, 3, 329-334.
ported by Miiller (1966)indicate that fluorine partiAllen, J. (1976) Silicate-Carbonate Equilibria in Calcareous
tions preferentially into biotite by a factor of 1.7 to
Metasediments of the Tudor Township Area, Ontario. Ph.D
3.0. Thus applying this partitioning factor to a
Thesis, Queens University, Kingston, Ontario.
muscovite coexisting with a fluorbiotite (XF > 0.86) Allman, R. and Kortnig, S. (1972)Fluorine. In K. H. Wedepohl,
Ed., Handbook of Geochemistry,Vol. II/1, ch. 9, Springer,
would yield a fluormuscovite.
Berlin.
The mineral montdorite, a mica of unusual comBailey, S. W. (1975) Cation ordering and pseudosymmetryin
position describedby Robert and Maury (1979),has
layer silicates. American Mineralogist, 60, 175-18'7.
XFI(XF+XOH+XO) : 0.54, but Fleischer (1979) Berg, A. N. van den (1975)Anion Distribution amongCoexisting
implies that the hydroxyl end-memberis the minerMinerals of Grenville Marbles. M.S. Thesis,The University of
Michigan, Ann Arbor.
al to which the namemontdoriteapplies.Sinceonly
A. W. R.. Bevan, J. C., and Francis, J. G. (1977)
Bevan.
one occurrence of montdorite has been described,
Amphibole in the Mayo-Belwa meteorite: First occurrencein
its compositional variation cannot be evaluated.
an enstatite achondrite. Mineralogical Magazine, 41, 531-534.
Other fluorine end-member micas and amphi- Bohlen, S. R., Essene,E. J., and Hoffman,K. S. (1980)Feldspar
boles will eventually be found if analysisof fluorine
and oxide thermometry in the Adirondacks: an update. Geological Societyof America Bulletin, Part 1,91, ll0-113.
percent
is routinely undertaken. Only about thirty
Borley,
G. D. (1963)Amphiboles from the Younger Granites of
of the 1217amphiboleanalysesreportedby Leake
Nigeria. Part 1. Chemical classification.Mineralogical Maga(1968)have reported fluorine values and few microzine. 33. 358-376.
probe analyses currently include it on a routine Borley, G. and Frost, M. T. (l%3) Some observationson
igneous ferrohastingsites. Mineralogical Magazine, 33, 646basis. In general, amphiboles and micas from high
662.
grade marbles, skarns, granulite facies rocks and
Brown,
P. E., Essene,E. J., and Kelly, W. C. (1978)Sphalerite
granites
high-level
may have significant substituted
geobarometry in the Balmat-Edwards district, New York.
fluorine. In addition the dry extraterrestrial enviAmerican Mineralogist, 63, 250-257.
ronments found in meteorites and lunar rocks may Buddington,A. F. (1939)AdirondackIgneousRocks and Their
produce fluorine and oxygen-rich, hydroxyl-poor
Metamorphism. Geological Society of America Memoir 7.
M., Sueno,S., Prewitt, C. T., and Papike,J. J. (1973)
Cameron,
(Olsen
Frondel,
1975;
Bevamphiboles
et al.,1973;
High temperature crystal chemistry of Na-fluor-richterite.
describe
kaersuanet aI.,1977).Floranet al.(1978)
Transactions, American GeophysicalUnion, 54, 1230.
tite in the Chassigny meteorite and report qualita- Comeforo, J. E. and Kohn, J. A. (1954)Synthetic asbestos
tive ion microprobe analyses which may indicate
investigations I. Study of synthetic fluor-tremolite. American
Mineralogist, 39, 537-548.
that XF > XOH. Quantitative electron microprobe
analyses for fluorine could be used to determine Dana, E. S. (1920)DescriptiveMineralogy,6th ed., John Wiley
and Sons Incorporated, New York.
whether this phaseis fluorkaersutite. SeveraldifferRockDeer, W. A., Howie, R. A., and Zussman,J. (1962,1963)
ent kinds of amphiboles and micas have been reForming Minerals. Vol. 2, Vol. 3. John Wiley and Sons
ported from lunar rocks, but fluorine was either not
Incorporated, New York.
analysedfor or there was concern that the reported Doelter, C. (1912, 1914, l9l7) Handbuch der Mineralchemie.
Steinkopff, Dresden.
fluorine was in error (Frondel, 1975).More complete chemical analyses of these minerals may re- Douglas, J. A. V. and Plants,A. G. (1968)Amphibole: a first
occurrencein an enstatitechondrite.Meteorites,4, 166.
veal some new varieties of amphiboles,possibly Engel, A. E. J. and Engel, C. G. (1953)Grenville seriesin the
including fluortschermakite and fluorkaersutite.
NW Adirondack Mountains, New York: Part I General features of the Grenville series, and Part 2 Origin and MetamorThese studies may prove significant in view of the
544
PETERSEN ET AL.: FLUORINE MICAS AND AMPHIBOLES
phism of the major paragneiss.GeologicalSociety of America
Bulletin, 64, 1010-1M7.
Fedoseev, A. D., Grigor'eva, L. F., Chigareva,O. G., and
Romanov, D. P. (1970)Synthetic fibrous amphibolesand their
properties. American Mineralogist, 55, E54-863.
Fleischer, M. (1979) Montdorite. American Mineralogist, 64,
l 3 3 l.
Fleischer, M. (1980)Glossary of Mineral Species.Mineralogical
Record Incorporated,Bowie.
Floran, R. J.. Prinz, M., Hlava, P. F., Kecl, K., Nehru, C. E.,
and Hinthorne, J. R. (1978) The Chassigny meteorite: a
cumulate dunite with hydrous amphibole-bearingmelt inclusions. Geochimica et CosmochimicaActa. 42. 1213-1229.
Frondel, J. (1975) Lunar Mineralogy. Wiley and Sons, New
York.
Gibbs, G. V., Miller, J. L., and Shell, H. R. (1962)Synthetic
fl uormagnesio-richterite.American Mineralogist, 47, 7 5-82.
Gibbs, G. V. and Ribbe, P. H. (1969)The crystal structuresof
the humite minerals: I Norbergite. American Mineralogist, 54,
376-390.
Gunow, A. J., Ludington, S., and Munoz, J. L. (1980)Fluorine
in micas from the Henderson molybdenite deposit, Colorado.
Economic Geology,75, ll27-ll3l.
Harrington, I!. J. (1903)On the composition of some Canadian
amphiboles. American Journal of Science, 165,392-394.
Hawthorne, It. C. (1978)The crystal chemistry of the amphiboles
VIII. The c:rystalstructure and site chemistry of fluorriebeckite. Canadian Mineralogist, 16, 187-194.
Hazen, R. M. and Burnham,C. W. (1973)The crystalstructures
of one-laye;rphlogopiteand annite. American Mineralogist,58,
889-900.
Hintze, C. (19M, 1933)Handbuchder Mineralogie,Vols. I and
2, Walter de Gruyter Companie, Berlin.
Huebner, J. S. and Papike, J. J. (1970) Synthesis and crystal
chemistry of sodium-potassiumrichterite, (Na,K)NaCaMg5
SiEO22(OH,F)2:A model for amphiboles. American Mineralogist,55, 1973-1922.
Jacobson,R. R. E., Macleod, W. N. and Black, R. (1958)Ringcomplexesin the yonger granite province of northern Nigeria.
Geological Society of London Memoirs 1,7-79.
Jakob, J. and Parga-Pondal,L (1932)Geitrage zur chemischen
konstitution der Glimmer. X. Mittelung: Uber die rolles des
Titans in den phlogopiten. Zeitschrift fiir Kristallographie, 82,
can Mineralogist, 58, 249-254.
Mercolli, I. (1980)Fluor-verteilung in Tremolit und Talk in den
metamorphen Dolomiten des Campolungo (Tessin) und ihre
phasen petrologische Bedeutung. SchweizerischeMineralogische und PetrographischeMitteilungen, ffi , 3l-44.
Moore, J. N. and Kerrick, D. M. (1976)Equilibria in siliceous
dolomites of the Alta Aureole, Utah. American Journal of
Science. 276. 504-524.
Miiller, G. (1966) Die Beziehungen zwischen der chemischen
ZusammensetzengLichtbrechung, und Dichte einiger Koexistierender Biotit, Muscovit, und Chlorit aus granitischenTiefengesteinen.Contributions to Mineralogy and Petrology, 12,
173-t91.
Munoz, J. L. and Ludington, S. C. (1977)Fluoride-hydroxy
exchangein synthetic muscovite and its applicationto muscovite-biotite assemblages.American Mineralogist, 62, 304-308.
Olsen, E. (1967) Amphibole: First occurrence in meteorite.
Science,156,6l-62.
Olsen, 8., Huebner, J. S., Douglas,J. A. V. and Plant, A. C.
(1973) Meteoritic amphiboles. American Mineralogist, 58,
861-872.
Rice, J. M. (1976) The influence of OH-F substitution on the
stability of talc in metamorphosedsiliceousdolomite. Transactions, AmericanGeophysicalUnion, 57, 338.
Rimsaite,J. H. Y. (1967)Studiesof rock-formingmicas.Geological Survey of CanadaBulletin 149, l-82.
Robert, J. L. and Maury, R. C. (1979)Natural occurrence of a
(Fe, Mn, Mg) tetrasilicic potassium mica. Contributions to
Mineralogyand Petrology,68, ll7-123.
Ross, M., Smith, W. L. and Ashton, W. H. (1968)Triclinic talc
and associatedamphibolesfrom Gouverneur mining district,
New York. American Mineralogist, 5t, 7 5l-:l 69.
Skippen G. B. (1971)Experimental data for reactionsin siliceous
marbles.Geology,79, 457481.
Slaughter,J., Kerrick, D. M. and Wall, V. I. (1975)Experimental and thermodynamic study of equilibria in the systemCaGMgO-SiO2-H2HO2. American Journal of Science,275, 143162.
Stemple, I. S. and Brindley, G. W. (1960)A structural study of
talc-tremolite relations. Journal of the American Ceramic
Society, 41, 34-42.
Sundius, N. (1945) The composition of eckermannite and its
position in the amphibole group. Arsbok Sveriges Geologie
27r.
Undersok, 39.
Kearns, L. 8., Kite, L. 8., Leavens,P. B. and Nelen,J. A.
Tobi, A. C. (1956) A chart for measurementof optical axial
(1980)Fluorine distribution in the hydrous silicate minerals of
angles.American Mineralogist,41, 516-618.
the Franklin Marble, Orange County, New York. American Ulrych, J. (197E)Magnesioarfvedsonitefrom fenites near Hurky
Mineralogist, 65, 557-562
in the Cista massif (West Bohemia). Casopispro Mineralogii a
Kohn, J. A. and Comeforo, J. E. (1955)Synthetic asbestos
Geologii,23,67-:70.
investigations II. X-ray and other data on synthetic fluor- Valley J. W. and Essene,E. J. (1980)Calc-silicatereactionsin
richterite. -edenite. and -boron edenite. American MineralAdirondack marbles: the role of fluids and solid solutions:
ogist,40, 410421.
Summary. Geological Society of America Bulletin, Part l, 91,
Kwak, T. A. P. and Askins, P. W. (1981)Geologyand genesisof
ll4-117. Part II. 91.720-815.
the F-Sn-W GBe-Zn) Skarn (Wrigglite) at Moina, Tasminia. Valley, J. W., PetersenE. U., Essene,E. J. and Bowman,J. R.
Economic Geology, 76, 439461 .
(19E2)Fluorphlogopite and fluortremolite in Adirondack marLeake, B. E. (1968) A catalog of analyzed calciferous and
bles and calculated C-O-H-F fluid compositions. American
subcalciferous amphiboles together with their nomenclature
Mineralogist, 67, 545-557.
and associatedminerals. Geological Society of America Spe- Westrich, J. R., (1981)F-OH exchangeequilibria betweenmicacail Paper,9E, l-210.
amphibole pairs. Contributions to Mineralogy and Petrology,
rn press.
Leake, B. E. (1978) Nomenclature of amphiboles. American
Mineralogist, 63, 1023-1052.
McCauley, J. W., Newham, R. E. and Gibbs, G. V. 0973)
Manuscriptreceived,February 13,I9E1;
Crystal structure analysisof synthetic fluorphlogopite.Ameriacceptedfor publication,January ll, 1982.