27
The Canadian Mineralogist
Vol. 51, pp. 27-37 (2013)
DOI : 10.3749/canmin.51.1.27

NASHITE, Na3Ca2[(V4+V5+9)O28]•24H2O, A NEW MINERAL SPECIESFROM THE YELLOW CAT MINING DISTRICT, UTAHAND THE SLICK ROCK MINING DISTRICT, COLORADO:
CRYSTAL STRUCTURE AND DESCRIPTIVE MINERALOGY
Anthony R. KAMPF§
Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard,
Los Angeles, CA 90007, U.S.A.

John M. HUGHES
Department of Geology, The University of Vermont, Burlington, VT 05405, U.S.A.

Joe MARTY
5199 E. Silver Oak Rd., Salt Lake City, UT 84108, U.S.A.

Francis H. BROWN
Department of Geology and Geophysics, University of Utah, Salt Lake City, UT 84112, U.S.A.

Abstract
Nashite, Na3Ca2[(V4+V5+9)O28]•24H2O, is a new mineral species from the Little Eva mine, Yellow Cat District, Grand County,
Utah, and the St. Jude mine, Slick Rock district, San Miguel County, Colorado, USA. Nashite occurs as blades on a corvusitemontroseite-bearing sandstone block intimately associated with calcite, gypsum, huemulite, pascoite, rossite, and sherwoodite.
Nashite is bluish-green, with a light bluish-green streak. The mineral is transparent, with a subadamantine luster. Nashite does not
fluoresce in short- or long-wave ultraviolet radiation, and has a hardness ca. 2. Nashite has a brittle tenacity, irregular fracture,and one good cleavage on {010}. Density (calc.) = 2.350 g/cm3 based on the empirical formula and single-crystal cell data, anddensity (calc.) = 2.343 g/cm3 based on the ideal formula and single-crystal cell data. Nashite is biaxial (–), with α 1.737(3),β 1.762(6), and γ 1.775(3). 2Vmeas = 70(2)° and 2Vcalc = 71°. Optic orientation is Y = b, X ≈ a. The mineral is pleochroic, with
X greenish blue, Y yellowish green, and Z yellow, with X > Y >> Z. Electron probe microanalysis and the crystal structure solution
gave the empirical formula (based on O = 52): (Na3.063K0.007)Σ3.070(Ca1.984Sr0.039)Σ2.019[(V4+V5+9)O28]•24(H1.995O). The simplified
formula is Na3Ca2[(V4+V5+9)O28] •24H2O. Nashite is monoclinic, P21/n, with a 10.0099(3), b 21.8472(7), c 11.1504(7) Å, andβ 116.584(8)°. The strongest four lines in the diffraction pattern are [d in Å(I)(hkl)]: 9.044(100)(111, 101), 8.350(64)(110),10.995(46)(020), and 2.9942(29)(331, 332, 303, 071, 310). The atomic arrangement of nashite was solved and refined to R1 =0.0293. The structural unit in nashite is a partially-reduced decavanadate group, with a composition of [(V4+V5+9)O28]7–; chargebalance in the structure is maintained by the [Na3Ca2(OH2)22•2H2O]7+ interstitial unit. The interstitial unit consists of chains of
Na1 and Na2 octahedra and an irregular CaO2(OH2)6 polyhedron. The chains are linked to the structural unit by direct bonding
to oxygen atoms of the [(V4+V5+9)O28]7– group and extensive hydrogen bonding between the H2O molecules of the interstitialgroup and the oxygen atoms of the structural unit. The mineral is named for Dr. Barbara P. Nash (b. 1944), Professor of Geology
and Geophysics at the University of Utah.
Keywords: nashite; new mineral species; decavanadate; crystal structure; Little Eva mine, Yellow Cat District, Grand County,
Utah, USA, St. Jude mine, Slick Rock district, San Miguel County, Colorado, USA§

E-mail address: akampf@nhm.org

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the canadian mineralogist

Introduction
The uranium and vanadium (Uravan) deposits
of Colorado and Utah have been a rich source ofore in the production of these metals. Throughout
the Colorado Plateau Uravan Mineral Belt, uranium
and vanadium minerals occur together in bedded orroll-front deposits in the sandstone of the Salt Wash
member of the Jurassic Morrison Formation (Carter& Gualtieri 1965, Shawe 2011). Recent collecting atthese deposits by one of the authors (JM) has revealed
numerous secondary vanadium minerals that result fromoxidation of vanadium ore bodies under near-surface
conditions. With the exception of martyite, Zn3(V2O7)(OH)2•2H2O (Kampf & Steele 2008a), which contains
the divanadate group, [V2O7] 4–, and dickthomssenite,
Mg(V2O6)•7H2O (Hughes et al. 2001), which contains[VO3] – vanadate chains, all of the new species containthe decavanadate anionic complex, [V10O28] 6–, foundin the pascoite family of minerals. The new minerals
that contain (V10O28) 6– sensu stricto include hughesite,
Na3Al(V10O28)•22H2O (Rakovan et al. 2011), lasalite,
Na2Mg2(V10O28)•20H2O (Hughes et al. 2008), magnesiopascoite, Ca2Mg(V10O28)•16H2O (Kampf & Steele
2008b), and postite, Mg(H2O)6Al2(OH)2(H2O)8(V10O28)•
13H 2O (Kampf et al. 2012). In addition, the firstminerals that contain protonated decavanadate groups
have also been discovered, including rakovanite,
Na3[H3(V10O28)]•15H2O (Kampf et al. 2011a) andgunterite Na4(H2O)16[H2(V10O28)]•6H2O (Kampf et al.
2011b). The recent collecting also yielded crystals of
the decavanadate huemulite, Na4Mg(V10O28)•24H2O(Gordillo et al. 1966), suitable for structure determination (Colombo et al. 2011). The only other previously known pascoite family mineral, hummerite,
K 2Mg 2(V 10O 28)•16H 2O (Hughes et al. 2002), alsocomes from the Uravan deposits. Sherwoodite, whichcontains a 14-vanadoaluminate complex anion of[AlV14O40]n– composition, also forms in the Colorado
Plateau Uravan deposits (Evans & Konnert 1978).
Herein we describe another new secondary mineralfrom the Uravan deposits, the first with a [(V4+V5+9)
O28] vanadylnonavanadate polyanion. The new species
was discovered in the St. Jude mine, Slick Rock district,
San Miguel County, Colorado, USA. Better crystals
suitable for structure determination and completion of
the characterization were subsequently found in the
Little Eva mine, Yellow Cat District, Grand County,
Utah. The mineral is named for Dr. Barbara P. Nash(b. 1944), Professor of Geology and Geophysics at
the University of Utah. Professor Nash is particularly
known for her many contributions to the geochemistry
and petrogenesis of volcanic systems. Dr. Nash has
previously served as Associate Editor of the American
Mineralogist, and has been the director of the Electron
Microprobe Laboratory at the University of Utah since
its inception in 1970. Recently, Dr. Nash has worked

extensively on the chemical analysis of vanadiumminerals from the Colorado Plateau, contributing to
the descriptions of several new minerals (gunterite,
hughesite, postite, and rakovanite). The new mineraland name were approved by the Commission on New
Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2011–105).
The type specimens of nashite are deposited in the
Natural History Museum of Los Angeles County, 900
Exposition Boulevard, Los Angeles, CA 90007, USA.
The holotype and one cotype from the Little Eva mine,
Yellow Cat District, Grand County, Utah, USA, areassigned catalogue numbers 63583 and 63584, respectively; three cotypes from the St. Jude mine, SlickRock District, San Miguel County, Colorado, USA, areassigned catalogue numbers 63585, 63586, and 63587.

Occurrence
In the Little Eva mine, nashite was found on sandstone blocks. Crystals were found growing as blades
on a corvusite-montroseite-bearing sandstone block
intimately associated with calciodelrioite (Kampf et al.
2012), calcite, gypsum, huemulite, pascoite, rossite,and sherwoodite. Other minerals found nearby include
andersonite, ansermetite, cobaltomenite, dickthomssenite, ferroselite, lasalite, martyite, melanovanadite,natrozippeite, schrockingerite, native selenium, tyuyamunnite, and uraninite. The mineral occurs in a similarassemblage at the St. Jude mine, Slick Rock district,
San Miguel County, Colorado, USA. At both localities
the mineral is rare.
The mineral forms from the oxidation of montroseitecorvusite assemblages in a moist environment. Mining
operations have exposed unoxidized and oxidized
phases; in addition to nashite, other mixed-valence
V4+/V5+ vanadium minerals are found in the association(sherwoodite, melanovanadite), which suggests that
local oxidizing conditions can be controlled by the presence of organic matter and phases such as pyrite. Under
ambient temperatures and generally oxidizing nearsurface environments, water reacts with pyrite in thedeposit to form aqueous solutions with relatively low
pH. The various secondary vanadate phases that formed
depend upon Eh-pH and the presence of other cations(Na+, Ca2+, Mg2+, Al3+) (e.g., Evans & Garrels 1958).

Appearance and Physical Properties
Crystals of nashite are equant to tabular andcommonly occur in stacked parallel intergrowths.
Individual crystals are up to 0.3 mm in maximum
dimension (Figs. 1, 2). Nashite is bluish-green, witha light bluish-green streak. The mineral is transparent,with a subadamantine luster. Nashite does not fluorescein short- or long-wave ultraviolet radiation, and has ahardness of approximately 2.

NASHITE, A NEW MIXED-VALENCE DECAVANADATE

Fig. 1. SEM image of nashite crystals from the Little Eva
mine, Yellow Cat District, Grand County, Utah, USA.

29

times. Sodium, Ca, and V were analyzed with theirrespective spectrometers before analyzing for otherconstituents. Magnesium was analyzed, but was below
the limit of detection (0.03 wt.%). Raw X-ray intensities were corrected for matrix effects with a phi-rho-z
algorithm (Pouchou & Pichoir 1991).
There was no visible damage from the electron
beam; however, as is typical of hydrated decavanadate
phases (i.e., postite, rakovanite, hughesite, gunterite, andlasalite), nashite partially dehydrates under the vacuumof the microprobe chamber. This H2O loss results inhigher concentrations for the remaining constituents
than are to be expected for the fully hydrated phase.
Because insufficient material is available for a direct
determination of H2O, the H2O content was calculatedon the basis of the structure determination. The analyzed
constituents were then normalized to provide a total of
100% when combined with the calculated H2O.

Nashite has a brittle tenacity and one good cleavage
on {010}. No parting was observed, and the mineraldisplays irregular fracture. The density of nashite
could not be measured because the mineral dissolves inaqueous density liquids and there is insufficient material
for direct measurement. Density (calc.) = 2.350 g/cm3
based on the empirical formula and single-crystal celldata, and density (calc.) = 2.343 g/cm3 based on theideal formula and single-crystal cell data.

Optical Properties
The optical properties of nashite were determinedin white light. Nashite is biaxial (–), with α 1.737(3),β 1.762(6), and γ 1.775(3). The 2V was measured
as 70(2)° from extinction data using EXCALIBRW(Gunter et al. 2004), and 2Vcalc = 71°. Dispersion was
not observed directly, but is probably strong based upon
“anomalous” colors observed under crossed polars as
crystals approach extinction position. The optic orientation is Y = b, X ≈ a. The mineral is pleochroic: X
greenish-blue, Y yellowish green, and Z yellow, with X> Y >> Z. Gladstone-Dale compatibility [1 – (Kp/Kc)= –0.020], as calculated from the empirical formulausing the density derived from the single-crystal unit
cell, is excellent.

The Composition of Nashite
Analyses of nashite (32 analyses from eight crystals) from the Little Eva mine were performed at the
University of Utah using a Cameca SX-50 electron
microprobe with four wavelength-dispersive spectrometers. Analytical conditions were 15 keV accelerating
voltage, 10 nA beam current, and a beam diameter of 10
μm. Counting times were 10 seconds for each element
except Na, which was analyzed with five second countFig. 2. Crystal drawing of nashite (clinographic projection instandard orientation).

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the canadian mineralogist

The crystal structure determination (see below)
convincingly indicates that of the ten V atoms in the
decavanadate group, the approximate equivalent of one
V atom has a valence of 4+ and nine have a valenceof 5+. Consequently, in the EMP analysis, we allocated VO2 and V2O5 accordingly. The analytical data
are presented in Table 1. On the basis of O = 52, theempirical formula is (Na3.063K0.007)Σ3.070(Ca1.984Sr0.039)
4+ 5+
Σ2.019 [(V V 9 )O 28 ]•24(H 1.995 O). The simplified
formula is Na 3 Ca 2 [(V 4+ V 5+ 9 )O 28 ]•24H 2 O, which
provides ideal oxide wt.% values (Table 1) in excellent
agreement with the analytical data.

Crystal Structure: Experimental
Powder and single-crystal X-ray diffraction data
for nashite were obtained with a Rigaku R-Axis Rapid
II curved imaging plate microdiffractometer using
monochromatized MoKα radiation. The powder data
presented in Table 2 are in good agreement with those
calculated from the structure data. Observed d values
and intensities were derived by profile fitting using
JADE v. 9.3 software (Materials Data Inc.).
The Rigaku Crystal Clear software package wasused for processing of the structure data, including theapplication of an empirical absorption correction. The
structure was solved by direct methods using SIR2004(Burla et al. 2005). SHELXL-97 software (Sheldrick2008) was used, with neutral atom scattering factors,
for refinement of the structure. Details of the sample,
data collection, and structure refinement are provided
in Table 3, final atom coordinates and equivalentisotropic temperature factors in Table 4, and selectedbond distances and bond-valence values in Table 5. A
table of structure factors, a CIF file, and a table of anisotropic displacement parameters are available from the
Depository of Unpublished Data on the MAC website[document Nashite CM51_27].

Atomic Arrangement of Nashite
Minerals that contain the decavanadate group can
be considered members of the pascoite family, pascoite(Ca3V10O28•17H2O) being the first described decavanadate mineral. All of the minerals of the pascoite family
possess bipartite structures that contain a structuralunit and an interstitial unit, as elucidated by Hawthorne(1983). In all the pascoite family minerals, the[V10O28]6– decavanadate polyanion forms the structuralunit of the mineral, and the structural units are linked
by the interstitial unit, the cationic portion of the structure, with bonds of lower bond valence linking alkalis,
alkaline earths, aluminum, and OH and H2O groups tooxygen atoms of the structural unit (Hughes et al. 2008).
The structural unit in nashite
The structural unit in nashite is the (V10O28) polyanion, similar to that found in decavanadate-bearing
minerals. The (V 10O 28) polyanion consists of ten
distorted, edge-sharing octahedra. In the V2, V3, V4,
and V5 octahedra in nashite, each octahedron contains
one vanadyl bond, defined as a V5+–O bond less than
1.74 Å in length (Schindler et al. 2000). The V1 octahedron has two vanadyl bonds. In all cases, vanadyl bonds
are trans to the longest V–O bond(s) of the octahedra,
typical of the disposition of bonds in the octahedra of
the decavanadate polyanion.
Prior to the recent mineral discoveries listed abovethat illustrate chemical and structural variations in the
decavanadate group, the [V10O28]6– polyanion was the
only form of the [V10O28] group that had been foundin minerals. The structures of rakovanite and gunteritewith their triply and doubly protonated decavanadategroups, respectively, demonstrate that there are variantsof the decavanadate group in natural materials previously known only in synthetic materials (Duraisamy
et al. 2000).

TABLE 1. ANALYTICAL RESULTS FOR NASHITE
Const.

wt.%

Range

S.D.

Norm. wt.%

Ideal wt.%

Probe Standard

Na2O
K2O
CaO
SrO
V2O5
VO2*
V2O5*
H2O
Total

6.99
0.02
8.19
0.29
(66.98)
6.11
60.28
18.12†
100.005.84–8.13
0.00–0.07
7.21–8.89
0.13–0.45
59.25–70.76

0.61
0.02
0.38
0.09
3.14

6.15
0.02
7.21
0.26

6.04

5.38
53.05
27.94§
100.01

5.39
53.19
28.10
100.00albitesanidine
diopside
Sr titanate (syn)Y vanadate (syn)7.29* Apportioned in accord with the structure† By difference§ Based upon crystal structure with V5+ = 9, V4+ = 1 and 52 O atoms.

31

NASHITE, A NEW MIXED-VALENCE DECAVANADATETABLE 2. POWDER X-RAY DIFFRACTION DATA FOR NASHITE
Iobs

dobs (Å)

46 10.995(4)100 9.044(3)
64
7
15
2

8.350(3)7.445(11)
6.962(5)5.926(10)17 5.526(3)13 4.908(2)6 4.683(3)12 4.445(3)6 4.154(3)4 3.920(8)4 3.703(8)15 3.5014(18)10 3.375(5)11 3.298(6)7 3.184(3)29 2.9942(13)13 2.8362(11)dcalc (Å) Icalc
10.9236
9.07148.94088.28337.36466.91885.88105.64645.54165.46185.36454.93664.87864.86084.66254.66094.47584.47044.41004.40614.1416
4.13743.92663.70343.65503.50733.48953.48443.37283.3632
3.3586
3.29173.2861
3.17993.04312.99952.99832.9803
2.97852.95642.94702.87522.83942.82512.82462.8232hkl

49 0 2 0
45 0 1 1
55 1 0 1
68 1 1 0
5 021
15 1 2 1
3 031
3 131
4 101
2 040
3 112
1 122
6 211
1 012
2 140
2 141
1 200
1 202
1 131
1 132
2 220
1 222
1 150
2 103
2 112
1 123
7 211
7 213
1 160
4 221
4 223
3 301
5 052
8 023
3 161
1 331
2 332
3 303
6 071
4 310
3 170
2 323
2 043
2 153
2 260
3 262

Iobs

dobs (Å)

52.7574(15)152.6521(6)142.5686(8)32.505(2)92.4374(8)32.313(3)52.274(4)132.1605(13)42.1133(17)52.0746(17)102.0210(5)91.9650(6)81.9264(8)21.881(2)51.8509(4)61.8215(6)dcalc (Å) Icalc
2.77082.76702.74822.74572.65882.64832.64542.56382.56012.55912.50252.44182.43042.30792.30632.26482.26432.1653
2.15682.15542.1523
2.12302.10182.07452.07332.06242.02012.01912.0134
1.96191.9394
1.92351.91641.9156
1.88301.8733
1.84501.82591.82481.81871.8172
1.81461.8138

hkl

1 202
2 204
1 251
1 253
2 123
4 271
8 053
1 134
5 270
6 272
4 402
2 361
5 024
2 360
2 363
1 371
4 372
1 054
4 370
2 373
2 115
3 124
3 381
1 134
1 135
3 462
3 461
2 463
4 383
6 025
1 154
4 035
1 471
1 473
1 390
1 045
7 482
1 292
1 294
1 470
1 474
2 481
2 483

Iobs

dobs (Å)

11.7903(12)31.7521(8)21.7040(5)31.6649(4)21.6473(7)41.6147(5)31.5411(6)111.4841(10)21.4353(14)71.4123(4)31.3773(7)31.3479(13)31.3271(8)dcalc (Å) Icalc
1.79101.78821.75371.73921.70491.7014
1.69811.66351.6455
1.61711.61581.54081.53901.53781.5021
1.49751.48931.4832
1.48301.47001.46981.46791.4646
1.4412
1.42651.42311.41011.40961.40911.40851.4051
1.39801.37411.3682
1.3516
1.3513
1.34291.3411
1.3272
1.3242
1.3227hkl

1 0 12 1
1 336
1 246
1 094
1 256
1 353
1 382
4 613
1 366
1 392
1 395
1 237
1 3 10 2
1 3 10 5
1 1 14 1
1 354
1 0 14 21 2 11 5
1 257
1 393
1 453
1 457
1 3 11 2
1 0 15 1
1 703
1 714
1 3 14 1
1 682
1 684
1 1 15 2
1 3 13 1
1 037
1 4 10 2
1 338
1 3 11 6
1 345
1 444
1 448
1 358
1 4 14 2
1 0 10 6

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the canadian mineralogist

TABLE 3. CRYSTAL DATA, DATA COLLECTION, AND STRUCTURE
REFINEMENT DETAILS FOR NASHITE
Chemical formula
Formula weight
Temperature
Wavelength
Crystal size
Crystal system
Space group
Unit cell dimensions

VolumeZ
Density (calculated)
Absorption coefficientF(000)
Theta range for data collection
Index ranges
Reflections collected
Independent reflections
Max. and min. transmission
Structure solution technique
Structure solution program
Refinement method
Refinement program
Function minimized
Data / restraints / parameters
Goodness-of-fit on F2
Δ/σmaxFinal R indices
Weighting scheme
Largest diff. peaks

Na3Ca2[(V4+V5+9)O28]·24H2O
1009.77
293(2) K
0.71075 Å
0.050 x 0.090 x 0.110 mmmonoclinic
P21/n
a = 10.0099(3) Å
b = 21.8472(7) Åc = 11.1504(7) Å
β = 116.584(8)°2180.67(17) Å322.307 g/cm3
2.437 mm–11478
3.46 to 25.02°–11 ≤ h ≤ 11, –26 ≤ k ≤ 26, –13 ≤ ℓ ≤ 13
17,8473,849 [R(int) = 0.0407]
0.8878 and 0.7753
direct methods
SHELXS-97 (Sheldrick 2008)
Full-matrix least-squares on F2
SHELXL-97 (Sheldrick 2008)
Σ w(Fo2 – Fc2)2
3849 / 36 / 380
1.092
0.043
R1 = 0.0293, wR2 = 0.0679
3144 data; 2σ(I)all data
R1 = 0.0404, wR2 = 0.0708
w = 1/[σ2(Fo2) + (0.0295P)2 + 2.2707P] where P =(Fo2 + 2Fc2)/3
0.368 and –0.434 eÅ–3

The minerals bearing the [V 10O 28] 6– group are
yellow-orange in color, typical of compounds that
contain vanadium only in the pentavalent oxidation state. The blue-green color of nashite suggested
the presence of both V4+ and V5+ in the crystal, yetparadoxically the structure solution demonstrated thepresence of a (V10O28) group, previously recognized
only with V5+. In addition, with the putative (V10O28)6–
group, charge balance was not achieved. Calculation ofbond-valence sums using parameters for pentavalent
vanadium showed two V atoms (V4 and V5) withbond-valence sums differing from the pentavalent stateby amounts atypical for such calculations in decavanadate groups, yielding 4.88 and 4.76 v.u., respectively(Table 5). Recalculation of those bond-valence sums
using parameters appropriate for mixed-valence, V4+/
V5+ sites (Table 5) yielded bond-valence sums of 4.43
and 4.56 v.u. for V4 and V5, respectively. Thus, the(V10O28) group in nashite is a vanadylnonavanadatepolyanion, with a mixed-valence vanadium composi-tion of [(V4+V5+9)O28]7–. Although mixed-valence V4+/
V5+ minerals are well-known (Evans & Hughes 1990),
nashite is the first known mineral to incorporate amixed-valence (V10O28) group in its atomic arrangement. In biological systems, a mixed-valance V4+/V5+(V10O28) compound has been synthesized; Ramasarma(2007) described a mixed-valence V4+/V5+ blue decavanadate compound that, when oxidized with hydrogen
peroxide, turns to a yellow-orange compound that
contains the [V10O28]6– polyanion with only pentavalent vanadium. Ramasarma (2007) further noted thatthe reduced (4+) vanadium atoms in the decavanadatepolyanion can undergo reversible redox changes.
Nashite displays the blue-green color typical ofintervalence charge transfer (IVCT) in vanadium
compounds. The two V octahedra that contain V4+
are V4 and V5, which are adjacent to each other at a
distance of 3.094 Å. Between the two octahedra, bondvalence calculations yield 1.01 atoms of V4+ and 0.99
V5+ distributed between the two sites, thus attaining

33

NASHITE, A NEW MIXED-VALENCE DECAVANADATETABLE 4. COORDINATES AND EQUIVALENT ISOTROPIC DISPLACEMENTPARAMETERS§ (Å2) OF ATOMS IN NASHITE

V1
V2
V3
V4
V5
Ca
Na1
Na2*
O1
O2
O3
O4
O5
O6
O7
O8
O9
O10
O11
O12
O13
O14
OW1
H1A
H1B
OW2
H2A
H2B
OW3
H3A
H3B
OW4
H4A
H4B
OW5
H5A
H5B
OW6
H6A
H6B
OW7
H7A
H7B
OW8
H8A
H8B
OW9
H9A
H9B
OW10
H10A
H10B
OW11
H11A
H11B
OW12
H12A
H12B
§U

x/a

y/b

z/c

Ueq

0.66529(6)0.40854(6)0.37017(6)0.61514(6)0.69161(6)0.21384(7)0.66412(16)0.0570(3)0.7841(2)0.7483(2)0.5317(2)0.7148(2)0.4819(2)0.3300(2)0.3104(2)0.5771(2)0.2922(3)0.2403(2)0.5057(3)0.7158(3)0.4456(2)0.8244(3)0.0166(3)0.031(4)–0.064(3)0.4622(3)0.473(4)0.534(4)0.0200(3)–0.071(3)0.024(4)0.0914(3)0.142(3)–0.003(2)0.3190(3)0.368(4)0.247(3)0.1987(3)0.263(3)0.118(3)0.9037(3)0.907(4)0.955(4)0.4376(3)0.362(3)0.424(4)0.5535(3)0.467(3)0.614(3)0.7885(3)0.839(4)0.723(4)0.5893(4)0.533(4)0.593(5)0.9289(3)0.888(4)0.937(5)0.00082(2)0.90728(2)0.04485(2)0.13848(2)0.86274(3)0.93734(3)0.30409(7)0.80727(16)0.94109(10)0.06185(10)0.98073(9)0.02066(9)0.06038(9)0.89318(10)0.85844(10)0.86040(10)0.02272(10)0.09909(10)0.10108(10)0.18815(11)0.18244(10)0.81479(11)0.89910(11)–0.1345(13)–0.1069(18)0.90335(12)–0.1015(19)–0.0739(17)0.01659(12)0.0131(18)0.0444(16)0.91867(14)–0.0721(19)–0.0716(19)0.01924(12)0.0132(18)0.0456(16)0.82121(14)–0.185(2)–0.1993(18)0.30461(13)0.3194(18)0.3289(16)0.30653(11)0.3206(16)0.2686(10)0.25584(13)0.2395(17)0.2298(15)0.30880(13)0.3363(15)0.2911(17)0.39388(16)0.4030(19)0.4178(17)0.76560(11)–0.2294(17)–0.2732(10)0.49774(5)0.32069(5)0.24803(5)0.42490(5)0.57045(5)0.92824(7)0.31612(15)0.6099(4)0.5290(2)0.4645(2)0.3179(2)0.6792(2)0.4678(2)0.1609(2)0.3853(2)0.3836(2)0.0927(2)0.2584(2)0.2534(2)0.3957(2)0.4022(2)0.5953(2)0.9760(3)0.026(3)–0.101(2)0.9745(2)–0.099(2)0.032(3)0.8453(3)–0.217(3)–0.096(3)0.6846(3)–0.361(4)–0.360(4)0.8373(2)–0.210(3)–0.206(4)0.8753(4)–0.037(2)–0.126(4)0.3271(3)0.255(2)0.395(3)0.3329(2)0.261(3)0.350(4)0.1003(3)0.086(4)0.095(4)0.5604(3)0.619(3)0.581(4)0.1650(4)0.202(4)0.107(4)0.8589(3)0.771(2)0.877(4)0.01536(13)0.01642(14)0.01721(14)0.01853(14)0.01877(14)0.02013(16)0.0358(4)0.0526(15)0.0205(5)0.0202(5)0.0166(5)0.0154(5)0.0159(5)0.0211(5)0.0189(5)0.0198(5)0.0225(5)0.0197(5)0.0204(5)0.0263(6)0.0197(5)0.0271(6)0.0261(6)0.05
0.05
0.0258(6)0.05
0.05
0.0318(6)0.05
0.05
0.0430(7)0.05
0.05
0.0306(6)0.05
0.0
0.0544(9)0.05
0.05
0.0358(7)0.05
0.05
0.0278(6)0.05
0.05
0.0409(7)0.05
0.05
0.0356(6)0.05
0.05
0.0631(10)
0.05
0.05
0.0359(6)
0.05
0.05

eq is defined as one third of the trace of the orthogonalized Uij tensor.
* Occupancy of Na2 = 0.496(6).

34

the canadian mineralogist

TABLE 5. SELECTED BOND DISTANCES (Å) AND BOND–VALENCE VALUES (VU) IN NASHITE
V1 –
O1
O2
O3
O4
O5
O5’
Mean, Sum:

Distance
1.693(2)1.697(2)1.898(21.905(2)2.148(2)2.151(2)1.915

Bond Valence
1.35
1.33
0.77
0.76
0.39
0.39
4.99

V2 –
O6
O7
O8
O4
O3
O5
Mean, Sum:

Distance
1.622(2)1.805(2)1.824(2)2.001(2)2.032(2)2.225(2)1.918

Bond Valence
1.63
0.99
0.94
0.59
0.54
0.32
5.01

V3 –
O9
O10
O11
O4
O3
O5
Mean, Sum:

Distance
1.623(2)1.800(2)1.811(2)2.012(2)2.014(2)2.217(2)1.913

Bond Valence
1.63
1.01
0.98
0.57
0.57
0.33
5.09

V4 –
O12
O13
O7
O11
O2
O5
Mean, Sum:

Distance
1.610(2)1.866(2)1.905(2)1.911(2)2.061(2)2.343(2)1.949

Bond Valence*
1.68(1.64)
0.84(0.76)
0.76(0.68)
0.75(0.67)
0.50(0.45)
0.23(0.23)
4.76(4.43)

V5 –
O14
O13
O8
O10
O1
O5
Mean, Sum:

Distance
1.616(2)1.824(2)1.876(2)1.907(2)2.094(2)2.315(2)1.939

Bond Valence*
1.66(1.61)
0.94(0.86)
0.82(0.74)
0.75(0.68)
0.46(0.42)
0.25(0.25)
4.88(4.56)

Ca –
OW1
OW2
OW3
OW4
O9
OW5
O6
OW6
Mean, Sum:

Distance
2.413(2)2.418(2)2.452(2)2.463(3)2.484(2)2.509(3)2.513(2)2.594(3)2.481

Bond Valence
0.31
0.30
0.28
0.27
0.26
0.24
0.24
0.20
2.10

Na1 –
OW7
OW8
OW9
OW10
OW11
O12
Mean, Sum:

Distance
2.346(3)2.357(3)2.397(3)2.438(3)2.473(4)2.657(3)2.445

Bond Valence
0.22
0.21
0.19
0.17
0.16
0.10
1.07

Na2 –
O14
O12
OW9
OW7
OW4
OW6
Mean, Sum:

Distance
2.266(4)2.305(4)2.379(5)2.525(5)2.546(4)2.666(5)2.484

Bond Valence
0.26
0.24
0.20
0.14
0.13
0.10
1.07

O1: 1.81
O4: 1.92
O7: 1.75
O10: 1.76
O13: 1.78

Bond Valence Sums for Oxygen Atoms of Decavanadate Group, Excluding H Bonds
O2: 1.83
O3: 1.88		
O5: 1.91
O6: 1.87
O8: 1.76
O9: 1.89
O11: 1.73
O12: 2.02
O14: 1.87

OW1: 0.31
OW4: 0.40
OW7: 0.36
OW10: 0.17

Bond Valence Sums for Oxygen Atoms of H2O Molecules, Excluding H Bonds
OW2: 0.30
OW3: 0.28
OW5: 0.24
OW6: 0.30
OW8: 0.21
OW9: 0.39
OW11: 0.16
OW12: 0.34

Bond valences were calculated using the terms in Brese & O’Keeffe (1991).
* The bond valences in parentheses for V4 and V5 were calculated using the parameters for mixed V4+/V5+ sites from Brown (1981).

NASHITE, A NEW MIXED-VALENCE DECAVANADATE

35

Fig. 3. The atomic arrangement of nashite projected down [100], depicting the [(V4+V5+9)
O28]7– structural unit and the [Na3Ca2(OH2)22•2H2O]7+ interstitial unit. The [(V4+V5+9)
O28]7– polyanion is depicted in orange and the Ca atom is red; Na atoms are yellow.
The unit cell is outlined in black, with the b axis horizontal.

charge-balance with the interstitial unit; the IVCT
between the vanadium atoms in V4 and V5 are the causeof the blue-green color in nashite.
The interstitial unit in nashite and its linkage
with the structural unit
The [(V4+V5+9)O28]7– structural unit is the anionic
portion of the atomic arrangement, and in nashite its
net charge of 7– is balanced by the interstitial unit,[Na3Ca2(OH2)22•2H2O]7+. The interstitial unit is formedof chains of [Na31(OH2)14]∞ , the vacancy a result of
the half-occupied Na2 site [refined Na2 occupancy =0.496(6)]. Like the oxide bronze mineral bannermanite(Hughes & Finger 1983), charge balance for the reduced
vanadyl atom is attained by a half-occupancy of the Na2site. Attached to the Na chains are the [Ca(OH2)6O2]
polyhedra, sharing an OW4–OW6 edge with Na2.
Figure 4 depicts the [Na3Ca2(OH2)22]∞7+ chains. Theinterstitial unit contains two isolated H2O molecules thatcomplete the [Na3Ca2(OH2)22•2H2O]7+ composition.
The interstitial unit is linked to the structural unitby hydrogen bonding and bonding between the oxygen
atoms of the vanadylnonavanadate polyanion and theinterstitial cations. Oxygen atoms O6, O9, O12, andO14, exterior atoms of the structural unit, bond directly
to the Na or Ca atoms of the interstitial unit. All oxygen
atoms of the structural unit except O5, O6, O9, and O12
are linked through hydrogen bonding to the interstitialunit, as they are all less than 2.2 Å from H atoms of
the interstitial unit.

Acknowledgments
The authors gratefully acknowledge Editor-in-Chief
Robert F. Martin for his long-standing and insightful
contributions to mineralogy through his service to The
Canadian Mineralogist. The manuscript was improvedby reviews by Associate Editor Olga Yakubovich, Dr.
Sergey Krivovichev, and an anonymous reviewer. This
study was funded, in part, by the John Jago Trelawney
Endowment to the Mineral Sciences Department of the
Natural History Museum of Los Angeles County andby grant NSF-MRI 1039436 from the National Science
Foundation to JMH.

References
Brese, N.E. & O’Keeffe, M. (1991) Bond-valence parameters
for solids. Acta Crystallographica B47, 192–197.

36

the canadian mineralogist

Fig. 4. The [Na3Ca2(OH2)22]7+ interstitial chain in nashite; Na = yellow, Na2 = orange.
Na2 sites are half-occupied. The addition of two isolated H2O molecules completes theinterstitial unit of [Na3Ca2(OH2)22•2H2O]7+.

Burla, M.C., Caliandro, R., Camalli, M., Carrozzini, B.,
Cascarano, G.L., De Caro, L., Giacovazzo, C., Polidori, G., & Spagna, R. (2005) SIR2004: an improved toolfor crystal structure determination and refinement. Journalof Applied Crystallography 38, 381–388.
Brown, I.D. (1981) The Bond Valence Method: An Empirical
Approach to Chemical Structure and Bonding. In Structure
and Bonding in Crystals, V. 2 (M. O’Keeffe & A. Navrotsky, eds.). Academic Press, Inc., (1–30).
Carter, W.D. & Gualtieri, J.L. (1965) Geology and uranium–vanadium deposits of the La Sal quadrangle, San
Juan County, Utah, and Montrose County, Colorado. U.S.
Geological Survey, Professional Paper 508, 82 p.
Colombo, F., Baggio, R., & Kampf, A.R. (2011) The crystal
structure of the elusive huemulite. Canadian Mineralogist
49, 849–864.
Duraisamy, T., Ramanan, A., & Vittal, J.J. (2000) Novelself-assembled decavanadate clusters forming 1D molecular chains and 2D molecular arrays: [HMTA-H…H2O][HMTA-CH 2 OH][H 3 V 10 O 28 {NaH 2 O) 4 }]•4H 2 O and[Na 2(H 2O) 10 ] [H 3V 10 O 28 {Na(H 2O) 2}]•3H 2O. Crystal
Engineering 3, 237–250.
Evans, H.T., JR. & Garrels, R.M. (1958) Vanadium in aqueous solution as applied to the interpretation of the Colorado
Plateau ore deposits. Geochimica et Cosmochimica Acta
15, 131–149.

Evans, H.T., Jr. & Hughes, J.M. (1990) The crystal chemistryof the natural vanadium bronzes. American Mineralogist
75, 508–521.
Evans, H.T., Jr. & Konnert, J.A. (1978) The crystal chemistryof sherwoodite, a calcium 14-vanadoaluminate heteropoly
complex. American Mineralogist 63, 863–868.
Gunter, M.E., Bandli, B.R., Bloss, F.D., Evans, S.H., Su,
S.C., & Weaver, R. (2004) Results from a McCrone
spindle stage short course, a new version of EXCALIBR,
and how to build a spindle stage. Microscope 52, 23–39.
Gordillo, C.E., Linares , E., Toubes , R.O., & Winchell, H.
(1966) Huemulite, Na4MgV10O24•24H2O, a new hydrous
sodium and magnesium vanadate from Huemul mine,
Mendoza Province, Argentina. American Mineralogist
51, 1–13.
Hawthorne, F.C. (1983) Graphical enumeration of polyhedralclusters. Acta Crystallographica A39, 724–736.
H ughes , J.M., C ureton , F.E., M arty , J., G ault , R.A.,
G unter , M.E., C ampana , C.F., R akovan , J., S om mer , A., & B rueseke , M.E. (2001) Dickthomssenite,
Mg(V2O6)•7H2O, a new mineral from the Firefly–Pigmay
mine, Utah: descriptive mineralogy and arrangement of
atoms. Canadian Mineralogist 39, 1691–1700.
Hughes, J.M. & Finger, L.W. (1983) Bannermanite, a new
sodium-potassium vanadate isostructural with -NaxV6O15.
American Mineralogist 68, 634–641.

NASHITE, A NEW MIXED-VALENCE DECAVANADATE

H ughes , J.M., S chindler , M., R akovan , J., & C ure ton , F.E. (2002) The crystal structure of hummerite,
KMg(V 5O 14)•8H 2O: bonding between the [V 10O 28] 6–
structural unit and the {K 2Mg2(H2O)16}6+ interstitial
complex. Canadian Mineralogist 40, 1429–1435.
Hughes, J.M., Wise, W.S., Gunter, M.E., Morton, J.P., &Rakovan, J. (2008) Lasalite, Na2Mg2[V10O28]•20H2O,
a new decavanadate mineral species from the Vanadium
Queen Mine, La Sal District, Utah: Description, atomic
arrangement, and relationship to the pascoite group ofminerals. Canadian Mineralogist 46, 1365–1372.
Kampf, A.R., Hughes, J.M., Marty, J., Gunter, M.E., &Nash, B. (2011a) Rakovanite, Na3{H3[V10O28]}•15H2O,
a new species of the pascoite family with a protonateddecvanadate polyanion. Canadian Mineralogist 49,
889–898.
Kampf, A.R., Hughes, J.M., Marty, J., & Nash, B. (2011b)
Gunterite, Na4(H2O)16(H2V10O28)•6H2O, a new mineralwith a doubly-protonated decavanadate polyanion: Crystal
structure and descriptive mineralogy. Canadian Mineralogist 49, 1243–1251.
Kampf, A.R., Hughes, J.M., Marty, J., & Nash, B. (2012)
Postite, Mg(H 2O) 6Al 2(OH) 2(H 2O) 8(V 10O 28)•13H 2O, a
new mineral species from the La Sal mining district, Utah:
Crystal structure and descriptive mineralogy. Canadian
Mineralogist 50, 45–53.
Kampf, A.R., Marty, J., Nash, B.P., Plášil, J., Kasatkin,
A.V., & Škoda, R. (2012) Calciodelrioite, Ca(VO3)2·4H2O,
the Ca analogue of delrioite, Sr(VO3)2·4H2O. Mineralogical Magazine. 76, 2803-2817
Kampf, A.R. & Steele, I.M. (2008a) Martyite, a new mineralrelated to volborthite: Description and crystal structure.
Canadian Mineralogist 46, 687–692.

37

Kampf, A.R. & Steele, I.M. (2008b) Magnesiopascoite, a
new member of the pascoite group: description and crystal
structure. Canadian Mineralogist 46, 679–686.
Pouchou, J.-L. & Pichoir, F. (1991) Quantitative analysis
of homogeneous or stratified microvolumes applying
the model “PAP.” In Electron ProbeQuantitation (K.F.J.
Heinrich & D.E. Newbury, eds.). Plenum Press, New
York, (3l–75).
Rakovan, J., Schmidt, G.R., Gunter, M., Nash, B., Kampf,
A.R., M arty , J., & W ise , W.S. (2011) Hughesite,
Na3Al(V10O28)•22H2O, a new member of the pascoite family of minerals from the Sunday mine, San Miguel County,
Colorado. Canadian Mineralogist 49, 1253–1265.
Ramasarma, T. (2007) A Redox Profile of Vanadium. In Vanadium Biochemistry (M.A. Alves, ed.). Research Signpost,
Kerala, India, (45–74).
Schindler, M., Hawthorne, F.C., & Baur, W.H. (2000)
Crystal-chemical aspects of vanadium: polyhedral geometries, characteristic bond valences, and polymerization of(VOn) polyhedral. Chemistry of Materials 12, 1248–1259.
Shawe, D.R. (2011) Uranium-vanadium deposits of the SlickRock district, Colorado. U.S. Geological Survey, Professional Paper 576-F, 80 p., 20 plates.
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica A64, 112–122.

Received February 22, 2012, revised manuscript accepted
October 9, 2012.