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The Canadian Mineralogist
Vol. 39, pp. 1325-1331 (2001)

ORTHOMINASRAGRITE, V4+O (SO4) (H2O)5, A NEW MINERAL SPECIESFROM TEMPLE MOUNTAIN, EMERY COUNTY, UTAH, U.S.A.
FRANK C. HAWTHORNE§ AND MICHAEL SCHINDLER¶
Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada

JOEL D. GRICE
Research Division, Canadian Museum of Nature, Ottawa, Ontario K1P 6P4, Canada

PATRICK HAYNES
P.O. Box 1531, Cortez, Colorado 81321, U.S.A.

ABSTRACT
Orthominasragrite, V4+O (SO4) (H2O)5, is a new mineral species from Temple Mountain, Emery County, Utah. It occurs as
rounded aggregates (up to ~200 ␮m across) of irregular grains that are pale blue to bright blue, depending on size.
Orthominasragrite has a pale blue streak, a vitreous luster, and no observable fluorescence under ultraviolet light. It has nocleavage or parting. The Mohs hardness is ~1, and the calculated density is 2.00 g/cm3. Orthominasragrite is biaxial negative(pseudo-uniaxial) with ␣ 1.529(2), ␤ 1.534(2), ␥ 1.534(2), 2Vobs = 2(4)°, 2Vcalc = 0°, non-pleochroic, X = b, Y = c, Z = a.
Orthominasragrite is orthorhombic, space group Pmn21, a 7.246(4), b 9.333(6), c 6.210(4) Å, V 420.0(3) Å3, Z = 2. The strongest
seven lines in the X-ray powder-diffraction pattern [d in Å(I)(hkl)] are as follows: 4.699(10)(101,020), 3.322(5)(121),
2.865(4)(220), 2.602(3)(221,131,022), 3.734(2)(021), 3.622(2)(200), and 3.108(2)(002). Chemical analysis by electron
microprobe gave VO2 33.88, SO3 31.97, H2O (calc.) 36.30, sum 102.15 wt.%; the proportion of H2O was determined by crystalstructure analysis. The resulting empirical formula on the basis of 10 anions (including 5 H2O) is V1.014 S0.991 O5 (H2O)5; the endmember formula is VO (SO4) (H2O)5. Orthominasragrite is the orthorhombic form of (monoclinic) minasragrite. The crystal
structure was solved by direct methods and refined to an R index of 4.4% for 1007 observed (|Fo| > 5␴F) reflections measured
with an automated four-circle X-ray diffractometer using MoK␣ X-radiation. There is one V site occupied by V4+ and surroundedby one O atom and 5 (H2O) groups in an octahedral arrangement, with one short apical vanadyl bond (1.580 Å), four similar
equatorial bonds (<2.026 Å>), and one longer V–O bond (2.231 Å) trans to the vanadyl bond. The structure consists of isolated(V4+␾6) octahedra (␾: unspecified anion) and (SO4) tetrahedra linked by hydrogen bonds.
Keywords: orthominasragrite, new mineral species, crystal structure, minasragrite, vanadate, Temple Mountain, Utah.

SOMMAIRE
Nous décrivons ici l’orthominasragrite, V4+O (SO4) (H2O)5, nouvelle espèce minérale provenant du mont Temple, comtéd’Emery, au Utah. On la trouve en amas arrondis atteignant ~200 ␮m faits de cristaux irréguliers qui sont bleu pâle ou bleu
brillant, selon la taille des grains. L’orthominasragrite a une rayure bleu pâle, un éclat vitreux, et semble sans fluorescence souslumière ultra-violette et sans clivage ou plan de séparation. La dureté de Mohs est environ 1, et la densité calculée est 2.00 g/cm3.
Elle est biaxe négative (pseudo-uniaxe), avec ␣ 1.529(2), ␤ 1.534(2), ␥ 1.534(2), 2Vobs = 2(4)°, 2Vcalc = 0°, non-pléochroïque, X= b, Y = c, Z = a. Elle est orthorhombique, groupe spatial Pmn21, a 7.246(4), b 9.333(6), c 6.210(4) Å, V 420.0(3) Å3, Z = 2. Les
sept raies les plus intenses du spectre de diffraction, méthode des poudres [d en Å(I)(hkl)] sont: 4.699(10)(101,020), 3.322(5)(121),
2.865(4)(220), 2.602(3)(221,131,022), 3.734(2)(021), 3.622( 2)(200), et 3.108(2)(002). Une analyse chimique effectuée avec une
microsonde électronique a donné VO2 33.88, SO3 31.97, H2O (calc.) 36.30, somme 102.15% (poids); la proportion de H2O a étédéterminée par ébauche de la structure cristalline. La formule empirique qui en résulte, calculée sur une base de 10 anions (yinclus 5 H2O), est V1.014 S0.991 O5 (H2O)5; la formule idéale est VO (SO4) (H2O)5. L’orthominasragrite est la forme orthorhombiquede la minasragrite. Nous en avons résolu la structure cristalline par méthodes directes, avec affinement jusqu’à un résidu R de
4.4% pour 1007 réflexions observées (|Fo| > 5␴F), mesurées avec un diffractomètre automatisé à quatre cercles et rayonnement§¶

E-mail address: frank_hawthorne@umanitoba.ca
Current address: Institut für Mineralogie, Universität Münster, Correnstrasse 24, D-48149 Münster, Germany. E-mail address:
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THE CANADIAN MINERALOGISTMoK␣. Il y a un site V où loge le V4+, entouré par un atome d’oxygène et cinq groupes (H2O) définissant un agencement
octaédrique, avec une liaison apicale de type vanadyle (1.580 Å), quatre liaisons équatoriales semblables (<2.026 Å>), et une
liaison V–O plus longue (2.231 Å) disposée trans par rapport à la liaison vanadyle. La structure est faite d’octaèdres isolés(V4+␾6) (␾: anion non spécifié) et de tétraèdres (SO4) liés par des liaisons hydrogène.
(Traduit par la Rédaction)
Mots-clés: orthominasragrite, nouvelle espèce minérale, structure cristalline, minasragrite, vanadate, mont Temple, Utah.

INTRODUCTION
Mining and mineral-collecting activity in the Temple
Mountain region of Utah has revealed the occurrence ofsome novel and rare vanadium sulfate minerals associated with fossil trees of Triassic age. The late Howard
Evans, Jr. first recognized that these vanadium sulfates
could be new minerals, but further work was hinderedby the small size and hygroscopic nature of the crystals.
As a result of the successful solution and refinement of
the crystal structure, we identified orthominasragrite asa new mineral species. The new mineral and mineralname were approved by the Commission on New Minerals and Mineral Names, International Mineralogical
Association. The mineral’s name denotes its relation tominasragrite: it is the orthorhombic polymorph. The
holotype specimen of orthominasragrite is stored in thecollection of the Canadian Museum of Nature, Ottawa,
Ontario (catalogue number CMNMC 83269), with the
X-ray powder mount in the X-ray powder-mount reference collection at the X-ray-diffraction laboratory at the
Geological Survey of Canada.

PARAGENESIS
Orthominasragrite was found (by PH) at the North
Mesa mine group, Temple Mountain mining district,
Emery County, Utah. The mine group is located in thewest ½, southwest ¼ of section 35, Township 24 South,
Range 11 East. The host rock is the Shinarump conglomerate member of the late Triassic Chinle Formation. Orthominasragrite occurs in a silicified tree,
approximately 46 cm wide by 30 cm high by an undetermined length; there is a rim of coal 6–25 mm thickaround the tree. Pyrite has replaced part of the tree, andgroundwater has reacted with the pyrite to produce various colorless, white and yellow iron sulfate minerals,
accompanied by microscopic yellow crystals and yellow to green fine-grained aggregates of native sulfur.
The iron sulfates generally occur in the outer rim of coaland in the adjacent conglomerate. There is dense
submetallic to somewhat earthy, dull grey, radiating
material in the silicified tree, the probable source of theV that occurs in blue and green secondary vanadium
sulfate minerals, including orthominasragrite, minasragrite, and an as-yet undescribed sulfate of vanadium,
all of which are subtly different shades of blue.

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Specimens of these vanadium sulfate minerals leavea sticky resinous material on the fingers. Droplets of an
Fe–V-rich liquid are, in some cases, present on fracturesin freshly exposed tree fragments. This liquid is acidic,
destroying paper containers, and seeps from fractures
to evaporate and form vanadium sulfate minerals, including orthominasragrite.

PHYSICAL PROPERTIES
Orthominasragrite consists of rounded aggregates(up to 200 ␮m across) of irregular grains. The aggregates occur as blue-green crusts and efflorescences; individual grains are pale blue to bright blue, dependingon grain size. The streak is pale blue, the luster vitreous. No cleavage or parting was observed. The Mohs
hardness is difficult to measure accurately because of
the minute size of individual crystals, but it is approximately 1. The density could not be measured because of
the intimate association with other minerals identical inappearance; the calculated density is 2.001 g/cm3.
Optical properties were measured with a Bloss
spindle stage for the wavelength 590 nm using a gel filter. The indices of refraction are ␣ 1.529(2), ␤ 1.534(2),␥ 1.534(2), the calculated birefringence ␥–␣ is 0.005,(+)2V(meas.) 2°, 2V(calc.) 0°; orientation X = b, Y = c,
Z = a; there is no pleochroism.

CHEMICAL COMPOSITION
Crystals were analyzed with a Cameca SX–50 electron microprobe operating in wavelength-dispersion
mode, with an accelerating voltage of 15 kV, a specimen current of 20 nA, and a beam diameter of 5 ␮m.
The following standards were used: VP2O7 (V) and anhydrite (Ca). The crystals broke down almost immediately under the electron beam, presumably losing H2O,
and only single analyses could be made at any point;
subsequent analyses had totals (including calculated
H2O) exceeding 116 wt%. The data were reduced andcorrected by the PAP method of Pouchou & Pichoir(1984, 1985). The presence and quantity of H2O groups
were established by crystal-structure solution and refinement (Hawthorne & Grice 1990). The resultant chemical composition is given in Table 1, together with theformula unit based on 10 anions (including 5 H2Ogroups) pfu (per formula unit). The excess in wt.% total

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X-radiation. Intensity data were collected according to
the procedure described by Cooper & Hawthorne(2001). Data were corrected for Lorentz, polarization
and background effects, and reduced to structure factors. The final unit-cell parameters (Table 3) are basedon least-squares refinement of 1615 reflections (>10␴F). A total of 4897 reflections was measured out to60°2␪, with index ranges 8̄ ≤ h ≤ 8, 1̄0̄ ≤ k ≤ 9, 1̄3̄ ≤ l ≤12. Of the 1307 unique reflections, 1007 reflections
were considered as observed [| Fo | ≥ 5 ␴F].

STRUCTURE SOLUTION AND REFINEMENT

The powder-diffraction pattern was recorded with aGandolfi camera using Ni-filtered CuK␣ X-radiation.
Table 2 shows the X-ray powder-diffraction data fororthominasragrite, together with the refined unit-celldimensions. Unit-cell dimensions were also determinedon a Nicolet P4 automated 4-circle diffractometer witha CCD detector (Table 2).

Scattering curves for neutral atoms were taken fromthe International Tables for Crystallography (Ibers &Hamilton 1992). R indices are of the form given in Table
1, and are expressed as percentages. The Siemens
SHELXTL PLUS (PC version) system of programs wasused for this work.
The structure was solved by direct methods. Two
cation sites were identified by a combination of sitescattering values and local stereochemistry. All anions
were assumed to be oxygen (Z = 8), and the cation scattering indicated that the two cation sites are occupied
by V (Z = 23) and S (Z = 16), and the local stereochemistry is in accord with this. The structure refined rapidly
to an R index of ~5% for a model with anisotropic-displacement factors at all non-hydrogen atoms. At thisstage, a difference-Fourier map allowed identificationof the H-atom sites. These were added to the refinementwith the soft constraint that O–H ≈ 0.98 Å. Full-matrix
least-squares refinement of all atoms (with fixed isotropic-displacement factors on all the H atoms) converged
to an R-index of 4.4%. Positional and displacement parameters for the constrained refinement are given in
Table 4, and selected interatomic distances are listed inTable 5. Observed and calculated structure-factors areavailable from The Depository of Unpublished Data,
CISTI, National Research Council, Ottawa, Ontario
K1A 0S2, Canada.

SINGLE-CRYSTAL DIFFRACTIONDESCRIPTION OF THE STRUCTURE

A small crystal was attached to a glass fiber andmounted on a Siemens P4 automated four-circle
diffractometer equipped with a CCD detector and MoK␣The structure of synthetic V O SO4 (H2O)5 was described by Tachez & Théobald (1980) in space group
Pmn21, with a 7.234, b 9.304 and c 6.184 Å. The struc-over 100 is caused by incipient dehydration of the mineral during electron-microprobe analysis, which increases the weight percentages of non-H2O components.

X-RAY POWDER DIFFRACTION

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THE CANADIAN MINERALOGIST

ture is identical to that of the newly proposed mineral.
The experimental data relevant to our structure refinement are listed in Table 3, and the bond-valence summations are presented in Table 6.
Coordination of the cations
There is one S site, occupied by S and surroundedby four O atoms in a tetrahedral arrangement with a <S–
O> distance of 1.473 Å, equal to the grand <S–O> dis-1325 39#5-oct-01-2277-08

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tance of 1.473 Å reported for sulfate minerals byHawthorne et al. (2000). There is one V site, occupied
by V and surrounded by six O atoms in an octahedral
arrangement. There is one very short V–O distance of
1.580 Å, four intermediate-length V–O bonds in therange 2.019–2.033 Å and approximately orthogonal to
the short V–O bond, and one long bond of 2.231 Å transto the short V–O bond. The short V–O bond is a vanadylbond, the intermediate-length bonds are equatorial
bonds, and the long bond is a trans bond. This geometry is characteristic of [6]V4+, as discussed by Schindler
et al. (2000).
Hydrogen bonding
All H atoms were located at the final stages of refinement of orthominasragrite, and all are attached to O
atoms (bonded to V) to form (H2O) groups. The formula of orthominasragrite indicates five (H2O) groups
per V4+ cation; the O(1) atom receives 1.74 vu (valence
units) from the central V atom, and hence the anion must

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be an O atom, whereas the other ligands associated with
V receive ≤0.5 vu, and hence are (H2O) groups.
Details of the hydrogen-bonding scheme are given
in Tables 5 and 6, and Figure 1. The H(3) and H(4) atoms are linked to the O(3) atom, and each hydrogen
atom bonds to the O(5) anions, with H-acceptor distances of 1.76 and 1.73 Å, respectively, and O–H...O
angles of 160°. The H(5) and H(6) atoms are linked to
the O(4) atoms, and hydrogen bond to the O(6) and O(7)anions, with H-acceptor distances of 1.91 and 1.69 Å,
respectively, and O–H...O angles of 160 and 173°. These
values are typical for normal hydrogen bonds.
Structure topology
V O SO4( H2O)5 is built of isolated (V␾6) (␾: O,
H2O) octahedra and (SO4) tetrahedra. Hydrogen bondsof the four equatorial (H2O) groups link the (V␾6) octahedron to six (SO4)2– tetrahedra (Fig. 1), and each(SO4)2– tetrahedron is linked via hydrogen bonds to six(V␾6) octahedra (Table 4). The bond-valence sum incident at O(2) requires that this site is also occupied by an(H2O) group, but the refined H sites show an unreasonably small H(1)–O(2)–H(2) angle of 62(6)°. However,geometrical and bond-valence considerations show thatthe hydrogen atoms associated with O(2) must bond toO(1), the O-atom of the vanadyl bond. It seems prob-

FIG. 1. Coordination polyhedra and hydrogen bonding inorthominasragrite; (V␾ 6 ) octahedron: blue; (SO 4 )tetrahedron: yellow; H atoms: green circles; hydrogenbonds: broken lines. The variation in yellow shading
denotes height relative to the plane of the diagram.

FIG. 2. The (V␾6) and (SO4) polyhedra in orthominasragrite viewed down the c axis;
legend as in Figure 1.

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FIG. 3.

THE CANADIAN MINERALOGISTThe crystal structure of orthominasragrite viewed down the b axis; legend as in Figure 1.

FIG. 4. The crystal structure of minasragrite viewed along theb axis; legend as in Figure 1, the oxygen atom of the (H2O)
group is shown as a red circle.

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ORTHOMINASRAGRITE FROM TEMPLE MOUNTAIN, UTAH

able that the H atoms attached to O(2) are positionallydisordered such that, for any one local configuration,
one H atom occupies either the H(1) or H(2) site andhydrogen bonds to O(1), and the other H-atom does nothydrogen bond to any anion.
The octahedra and tetrahedra occur in different layers parallel to {110} (Fig. 2); it is also apparent from
Figure 2 that the octahedra and tetrahedra are not linked
directly in orthominasragrite. The structure of V O SO4(H2O)5 can thus be described as chains of (V␾6) octahedra linked by hydrogen bonds parallel to c (Fig. 3),
which are linked by hydrogen bonds to sulfate tetrahedra in the ab plane (Fig. 1).
Related structures
Orthominasragrite and minasragrite (Schaller 1917,
Smith & Marinenko 1973) are polymorphs, and hence
two of the three known polymorphs of V O(SO4) (H2O)5(Ballhausen et al. 1968, Tachez & Théobald 1980,
Tachez et al. 1979) are now known as minerals. Minasragrite is monoclinic, but the difference between the two
structures is not one of stacking sequence. Inspection of
the structure of minasragrite (Fig. 4) shows that the(V␾6) octahedron and the (SO4) tetrahedron share acorner to form a [V O (SO4) (H2O)4] group, and there isone (H2O) group (shaded red in Fig. 4) that does notlink directly to a cation, but is held in the structure solely
by hydrogen bonding. If we write the formula of eachmineral in terms of their structural unit and interstitial
species (Hawthorne 1985, 1990, 1997), this difference
becomes apparent: orthominasragrite [V O (H2O)5][(SO4)]; minasragrite: [V O (SO4) (H2O)4] (H2O).

ACKNOWLEDGEMENTS

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O2] (H2O)8, a comparison with guilleminite, Ba [(UO2)3(SeO3)2 O2] (H2O)3. Can. Mineral. 39, 797-807.
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________ (1990): Structural hierarchy in M[6]T[4]Øn minerals.
Z. Kristallogr. 192, 1-52.
________ (1997): Structural aspects of oxide and oxysalt
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________ & GRICE, J.D. (1990): Crystal-structure analysis as achemical analytical method: application to light elements.
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________, KRIVOVICHEV, S.V. & BURNS, P.C. (2000): The
crystal chemistry of sulfate minerals. In Sulfate Minerals –Crystallography, Geochemistry, and Environmental
Significance (C.N. Alpers, J.L. Jambor & D.K. Nordstrom,eds.). Rev. Mineral. Geochem. 40, 1-112.
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We thank Werner Baur, Peter Zavalij, Associate
Editor John Hughes, Joe Mandarino and Editor Bob
Martin for their comments on this paper. This work was
supported by Natural Sciences and Engineering Research Council of Canada Research, Equipment, Major
Installation and Major Facilities Access Grants to FCH.

SCHINDLER, M., HAWTHORNE, F.C. & BAUR, W.H. (2000):
Crystal-chemical aspects of vanadium: polyhedral
geometries, characteristic bond valences and polymerization of (VOn) polyhedra. Chem Mat. 12, 1248-1259.

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BALLHAUSEN, C.J., DJURINSKIJ, B.F. & WATSON, K.J. (1968):
The polarized absorption spectra of three crystalline
polymorphs of VOSO4•5H2O. J. Am. Chem. Soc. 90, 33053309.
B ROWN , I.D. & A LTERMATT , D. (1985): Bond-valence
parameters obtained from a systematic analysis of the
inorganic crystal structure database. Acta Crystallogr. B41,
244-247.
COOPER, M.A. & HAWTHORNE, F.C. (2001): Structure topology
and hydrogen bonding in marthozite, Cu2+ [(UO2)3 (SeO3)21325 39#5-oct-01-2277-08

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SMITH, M.L. & MARINENKO, J. (1973): A reexamination ofminasragrite. Am. Mineral. 58, 531-534.

________, ________, WATSON, K.J. & MERCIER, R. (1979):
Redétermination de la structure du sulfate de vanadylepentahydraté VOSO4•5H2O. Acta Crystallogr. B35, 15451550.

Received April 10, 2001, revised manuscript accepted
August 28, 2001.

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