FROMTHEA NEW ZINC SULPHATEGUNNINGITE,KENO HIII.GAIENA HItt AREA, YUKON1",1;^';l,tYfi,i?;,X#,Y;-"AssrRAcr
Gunningite, ZnSOr. HzO, occurs as sparsewhite efilorescenceson sphalerite in several
mines in the Keno Hill area, Yukon. The new mineral is monoclinic and isostructural
with the other members of the kieserite g1oup. Synthetic gunningite has cell dimensions
o l a : 7 . 5 6 6 , b : 7 . 5 8 6 , c : 6 . 9 5 4 A ; 9 : 1 1 5 ' 5 t i ' ; s p a c eg r o u p C 2 1 6 - A 2 / a(Pistorius, 1961). The unit cell contains four formula weights. Indexed r-ray powder
data of synthetic and natural material are given.^The strongest lines of the powdei
patternare 3.40 (s), 4.78 (ms),3.05 (m),2.61 (m) A.
Gunningite is very fine-grained, white in colour and streak, and has a hardness ofabout2$.Specific gravity of synthetic material is 3.195 (pycnometer);3.321 (calculated).
Refractiveindicesarea' : 1.570,r' : 1.630. X-rayfluorescenceanalysisofagunningite
precipitate gaveZnO 40.8, MnO 3.1, CdO 1.0, FeO 0.6, total 45.5%, in good agreementwith the theoretical value of 45.35% ZnO in gunningite.
The chemical relationships of gunningite with other members of the kieserite groupwere studied using synthetic material. Considerable quantities of magnesium, iron, andmanganesemay be substituted f.or zinc without efiect on the configuration of the r-ray
po*de. pattern. The association of other sulphates with gunningite in the Keno Hillarea is briefly discussed.
INrnooucttoN

The Keno Hill-Galena Hill district is in Central Yukon, 35 milesnortheast of Mayo and some 220 miles due north of Whitehorse. Thedistrict is noted for its silver-lead-zinc lodes which have been prolificproducers since their initial development in 1913.
In 1953, one of the present writers (R. W. B.) .commenced a detailed
investigation of the deposits in the Keno Hill area, the results of which
will be published in a forthcoming bulletin. Examination of the ores hasrevealed the presence of numerous supergene minerals derived from a
relatively simple primary source. This paper describes a new hydrous
zinc sulphate which has been found at several of the deposits, both on
Keno Hill and Galena Hill. The new mineral, called gunningite, is named
in honour of Dr. H. C. Gunning, a former member of the Geological
Survey of Canada, and, until 1959, Head of the geology department at
The University of British Columbia.
Gunningite was originally identified in the fall of 1960 as a barely
megascopic white effiorescence on a specimen from the Comstock-KenolPublishedby permissionof the Director,GeologicalSurveyof Canada"2roTEE

CANA.DIAN

MINERALOGIST

property (No. 23, Fig. 1). The sampleconsistedof brecciatedvein quartzcontaining numerous thin, irregular veinlets of arsenopyrite.All surfacesof the rock were heavily coated witJr dark reddish-brown goethite andlight yellow-gleen, fine-grained coatings of pharmacosiderite,scorodite,jarosites, and gypsum. Atop theseminerals, and last to have formed, werewhite irregular patches of the mineral now called gunningite. Although
r-ray powder photographs of the white sulphate showedit to be identicalto synthetic ZnSOn.HzO,other zinc minerals were absent and insufficientpure material was available for a spectrographicanalysis.
Some six months after this initial discovery, a thorough examinationof over a thousand specimensfrom the Keno area was undertaken andsmall amounts of gunningite were found in samplesfrom many additional
properties: on Keno Hill, at the Gambler workings (22)2, and in theNo. 9 vein system; on Galena Hill, at the Galkeno mine (11), the 200
and 650levels of the Calumet mine (8), the Cream (7), Silver King (1)and Leo 1-8 claims, the latter 4,000 feet northwest of the Silver
King mine.
OccunnBNcs
The depositsoI the Keno Hill-Galena Hill district are veins and lodes
in faults tJrat cut quartzites, phyllites, schists and greenstones(Fig. 1).
The principal primary minerals are siderite, quartz, galena, sphalerite,
chalcopyrite, pyrite, arsenopyrite and freibergite. These are altered in
the zones of oxidation to limonite, various hydrous manganeseoxides(wad), scorodite,jarosites,beudantite,bindheimite,cerussite,malachite,azz,Jrite,smithsonite, anglesite, and gypsum. In addition some nativesilver, pyrarglrite, and hawleyite occur in both the zones of oxidation
and reduction.
The gunningite is generally found closely associatedwith incipiently
oxidized sphalerite in the veins and lodes and on the old mine dumps. Inthe deposits the mineral is present in those parts that are relatively dry,and on the dumps the mineral appears on the oxidizing sphalerite after
long periods of hot dry weather. In all occurrencesthe mineral appears
as delicate effiorescencesdirectly on the surface of sphalerite, or as
effioiescenceson limonite, scorodite, gypsum, and other supergene
minerals closely associatedwith the zinc sulphide.
X-nav euo Cnvster,r,ocnapsrc Date
Gunningite,ZnSOa.HsO,is monoclinicand assumedto be isostructural
with the otJrermembers of the kieserite group. The unit cell dimensions
zNumbers in brackets refer to the mining properties shown in Figure 1.

2t2

THE CANADIANMINERALOGISTand structure were calculated from the x-ray difrraction
Pistorius (1961):

pattern

bya : 7.566*0.003 A; b : 7.586+0.008; c : 6.954+0.008
0 : 115'56tia:b:c : 0.9974:1:0.9167
the space group is Cnu - A2/a. X-ray powder data for gunningite andits synthetic equivalent are listed in Table 1. The identification of theminerals of the kieserite group by r-ray powder method is made difficult
by the similarity of the patterns of the various members. For purposes ofidentification in the present work, the group of reflections in the 20
region shown in Figure 3 were found to be characteristic for the iron,manganese, and zinc members.
Pnvsrcar. axo Oprrcer, PRopERTTEs
The natural mineral in all cases is so fine-grained as to be virtuallycryptocrystalline. Colour and streak are white, and the lustre vitreous.
The hardness is about 2!. Synthetic ZnSOa.H2O has a specific gravityof 3.195 (pycnometer; Gmelin, 1956), in fair agreement with the calculated value of 3.321 assuming Z : 4. The mineral is rapidly soluble incold water.
Refractive indices for the natural and artificial minerals are given
below. The latter was prepared by dehydration of reagent grade heptahydrate at about 100'C. (see pyrolysis curve, Fig. 2).

Synthetica' : L.570:L.576

Calumet 200 level ot' : 1.577
maximum ^(, _ d, :Y' : 1.630
r' : 1,630

0.06

Frc. 2. Pyrolysis curve of zinc sulphate (Duval, 1953).

2t3

GUNNINGITE

Comparisonwith the other membersof the kieserite group showsthat
the true birefringence of gunningite is probably about 0.06. All otherminerals in the group are biaxial positive.
Tesr.e 1. X-nav Powoen Data ror GuNrrNGrrB

ZnSOr.H:Oa

ComstockKeno(filteredCalumet
200 level

ZnSOr.Hs@(Pistorius, 1961)(synthetic, filteredcopper radiation)copperradiation)(filtered ironradiation)d(calc.)A/(est.) d(meas.)Ad(meas.)A -I(est.)d(meas.)A

4.825
0u
4.768
111
3.793
020
3 .428,3.402 1 1 1 , 2 0 0
2TI
3.367
r20
3.313
2@
3.068
2.563
TN
2.533
220
2.422
2LL
2.4L3022
2 . 3 8 6 , 2 . 3 8 4 3tT,22t
2.3M
031
2.338
137
2.t96
113
2.179
2L5
2.112
131
2.098
2.{2.067
L22
1.978
315
1 .896
04.0
4
1.878
4M
1.798
23t
3
1.738
204
1 .701
400
1.683
10422
1.657
240
6t.622
7042
1.589
333
5.
t.552
420
2
1 . 5 3 2 , 1 . 5 3 1 464,324
14'
1.502
5L . 4 7 9 : 2L34..
2L . 4 7 4t,. 4 7 3 051,157
4
r.455
349
1.435
433
1.411
151
32IiI
t.407
242
1 .3501 .320
115
1.310
r24
1.305
25r
1 . 2 8 3 , 1 . 2 8 1\fr,244
5
1.280
431 _
1 . 2 6 6 , 1 . 2 6 5440, 151
t . 2 6 4 , 1 . 2 6 3 060,L4t4
1.263
313

40
53
15
100
2327
45
15
38
3
43
l05
15
3
10
68t2

ms (2)

4.78

4.80

7

4.77

w
(1)
rw
lnw
ln (3)t?ru
ln (4)

3.77
3.40
3.33
3.29
3.05
2.55
2.5L

3.80
3.4L
3.36
3.32
3.06
2.56
2.52

2
10
3362+

3.78
3.40
3.32
3.29
3.05
2.56
2.5L

1/'

2.4r

no

2.4O

10

2.33

2.34

2"

2.33

2.rg

2.r9

32;L9

2.IO

2.LO2..

2.10/n1!)
tn (7) 'w

2 '05
1.963
1.898

2.06
1.968
L.902

2
32

2.05
1 .968
1.898

lnw
owb
w
ln (5)w
mw
lnw
w

1.807
].734
1.698
t.67t
L.649
L.6L7
1.582
r.ooo

1.815
I .735
1.705
r.675
1.654
L.62I
1.590
L.557

2

1.810

13
122'|

1.699
1.673
1.650
I,6T9' 1.586
1.557

l.4gg
1.468

1.505

, 1 /2

tnla
/

L.526
1.500
I .469

vw
w

l.MS
1.435

1I

L.M9

"^A/

112

1.356
L.327

f/tnw

JL.4r4\1.405
1.351
r.327
L.3L2
1.298
L.277

L.455
r.M0
1 .399

?nw

L.26L

ln(6)

J-lnw

f'r.524

1 .359

r.g3

1.281
1.266

t/2

2
1/2

r.737

r.437

r/2 lL.4L7
r/2 u.407
1lqr/2r/2
2

I .311t.297
1.277
I.26I2t4

THE CANADIAN
Tasls

1. X-nev

Powpenhht.

Dere ron GuNr.rrNcrre

ZnSOa.HzOb(synthetic, filteredcopper radiation)

ZnSOr.Hz@(Pistorius, 1961)d(calc.)AMINERALOGIST-I(est.)ComstockKeno(filteredcopperradiation)

Calumet200 level(filtered ironradiation)d(meas.)Ad(meas.)A /(est.)d(meas.)A

T.257

I0t

T.2M
L.227
1. 2 1 6
1.198
1.180
1.165
1.140
L.L24
1.099
1.087
L.052

ff
wu

tg o

1.019

1.021

owbffvugw
1rufff

1.203

I
L/2
L/2L/2

L.243
L.227
1.197

1.165
r.rM
1.101
1.089
1.056

tg3-f1m)w

0.9806
0.9723nlntensities obtained with Philips diffractometer on pure synthetic material bv
Pistorius (1,961),whose unit cell diniensions were used to calculatethe additional indicei
not accompanied by intensities.
bBaker's reagent grade ZnSOa.THzO dehydrated to the monohydrate. All films(columns 2, 3, 4) taken with 57.3 mm. dia. cameras; only Ka1 lines recorded below
il - I.40, Intensities are visual estimations, Comstock-Keno gunningite (column 3)
contains a small but undertermined quantiw of mansanesein'substitution for zini.
The_Calumet gunningite (column 4) isihe fir6t specimei shown in the table of spectrographic analyses.

Csrurcar, Date
Insufficient gunningite was available for a chemical analysis. As themineral is closely associatedwith sphalerite, considerableprecaution wasobserved in preparing the samples used for the spectrographic analysis
given in Table 2. Carbon electrodeswere directly loaded with material
carefully picked off the specimenswith the blunted tip of a fine sewingneedle. It was possible to obtain good samples in this manner as theTesr,s' 2. Spac'rrocRApurc ANALysEs or GuNNrNcrts
DescriptionMajor

Minor

Trace

Faint Trace

Calumet 200 level
Zn
Si, Cu, Mn
Mg
Calumet 200 level
Zn
Mg , Cu, Si
Leo 1-8Zn
Mg , Cu, Si
SynthetiC
Zn
Si, cuMg
oBaker's reagent gr:ade ZnSOa.THrO dehydrated to the monohydrate.

2L5GUNNINGITE

effiorescencesdo not cling to the rock surface, but are loosenedat theslightest touch. Hand picking of the selectedmaterial was done under a
50X binocular microscope.
Two specimensof gunningite from the same locality in the Calumet
mine 200level were immersedin a beaker of distilled water for 30 seconds,
a sufrcient time to dissolve the sulphate from the rock surface. The
solution was passedthrough fine filter paper (No. 42), gently evapordted,
dehydrated to the monohydrate, and the metallic elementsquantitatively
determined by x-ray fluorescenceanalysis (Table 3). Discoloration of the
precipitate indicated that some oxidation of iron had taken place. The
coincidence of the theoretical and analytical values reported below isfrankly regarded as being unusual for the r-ray method.
Tenr-n 3. X-nev Fr,uonsscENcE Ar.rar,vsrs or Gur.rr.rrr.rcrtBPnBctpttetp
ZnSOr.HrO

Calumet mine

(theoretical)
ZnO
45.35<SOs
M.6t
HrO
10.04

Spectrographic
determination
by G. R. Lachance.
X-ray fluorescence
additional
analysiishows
Ca,Mg, Si 10.01-{.lVd;Co,Ba,Cu,Al, Ag,
Ni, Pb,B (<.0L%),
RourroNsnrp oF GuNNINGITETo OTITERMBlrsBns oF THE
KrpsBnrrr Gnoup
It is probable that considerablemutual substitution of cations takes
place among kieserite (MgSOa.H2O),szomolnokite (FeSOn.HzO),andszmikite (MnSOr. HO). The relationshipsof theseminerals to gunningite
were studied by means of synthetic preparations formed by dissolving
in water weighedsamplesof the monohydrate sulphates,and evaporating
the solutions at approximately 90-100 Co.While the chemicalcompounds
encountered in these precipitates are not considered to be accurately
representativeof what may occur in nature, neverthelesssomeinteresting
relationships become apparent as the amount of substituting cation isincreased (Table 4). The ratios shown below are expressedas weightratios of the monohydratesulphates,'i,.e.,15mg. of FeSOa.HzOadded
to 30 mg. of ZnSOa.HgOis shown as Fe:Zn : L:2. The productswere
readily identified by their r-ray powder patterns as the transformationfrom one speciesto another is accompaniedby an abrupt change in thecharacteristic reflections shown in Figure 3.

2L6

THE CANADIANMINERALOGIST

Frc. 3. X-ray powiler patterns of the kieserite group minerals. (A) (Jrom top) Szmikite,synthetic. (B) Szomolnokite, Tyrol. (C) Kieserite, Wathlingen, Germany. (D) Gunningite,Keno Hill. (E) Synthetic ZnSOa.HzO. AII films taken with 57.3 mm. dia. cameras andmanganese-filtered iron radiation. The group of reflections between two notches serve todistinguish szomolnokite and szmikite from each other, as well as from kieserite or gunningiie.

2L7

GUNNINGITE
Tesr-B 4. Pnooucrs FonMso sv EvepoRATroN oF Sl'r-psarr
Sor-uuoNs
Product formed

Ratio
Zn:Mn 8:1
Zn:Mn 4:,IZn:Mn 7:3
Zn:Mn 3;2
Zt:Fe
Zn:Fe
Zn:FeZn':Fe2zl
1:1
l:2
2:5

Mol. /6 MnSOr.HzO
1l10
to39
Mol. VoFeSOr.HzO
32
49
65
70

gunningite
gunmnglte
szmlklte
szmikitegunningite
gunnlnglte..
szomolnoklte
szomolnokite

Though not thoroughly investigated, magnesium is apparently capableof adopting a similar substitutional role.
Comparison of the r-ray powder photographs obtained from the above
synthetic preparations leads to these conclusions: (1) considerable
atnounts of iron and manganese may be substituted for zinc in gunningite.
(2) A continuous series apparently exists between FeSOa'HsO andMnSOr.HzO with ZnSOa.HrO. (3) The presence of a large quantity ofiron in gunningite produces no change in cell edge and is not detectableby the film method. In marked contrast, significant increases in celldimensions accompany the addition of manganese.
AssocratBo Sur-pnetns IN THE KBNo Hrr-r- Anea
Additional members of the kieserite group occurring in the area areszomolnokite and szmikite, the former identified only from the 900 levelof the Calumet mine. Relatively pure szmikite is sparingly distributed inseveral levels of the same mine.
. Several grams of white and flesh-coloured emorescences collected fromspecimens on the dump of the Silver King property ate szmikites freeoi iron and unusually rich in zinc. The Silver King samples also containadmixed ilesite (MnSOr.4HzO) of similar composition.
Although the tetrahydrate sulphate of. zinc (znsoa.AHzo) has not yet
been identified from the Keno area, the mineral was found during thepresent study in association with bianchite (znso4.6HrO) from Goslar,
The *-ray powder pattern of the tetrahydrate is almost
i"t-.ny.
identical to that of FeSOa.4HzO, the minerals presumably being isostructural. It is likely that the zinc sulphate is much more common thanis implied by the fact that the species has never been described as a newone.

218

AHE CANADIANMINERALOGIST

Minerals containing additional water molecules beyond the tetrahydrate have not been reported in situ from the Keno Hill area, but
microscopic examination indicates that the most abundant and widelydistributed sulphate, rozenite (Fesoa.4Hro), was formed by dehydrationof a higher hydrate, presumably melanterite.s
OnrcrN
Gunningite is derived directly from the oxidation of sphalerite which
is known to have the composition (Zn,Fe,Cd,Mn)S in the Keno Hilldeposits. surface and ground waters carrying dissolved oxygen attack
the sphalerite, yielding soluble sulphates of. zinc, manganese,iron, andcadmium according to the following simple equations:ZnS (zinc component) * 2Oz-+ ZnSOa
MnS (manganesecomponent) f 2O2--+MnSOa
FeS (iron component) t 2Or-+ FeSOeCdS (cadmium component) * 2O2--+CdSOa
In the presenceof abundant water all of the soluble salts are removed.
If, however, the conditions are such that the supply of water is restricted
or evaporation takes place, the metal-bearing solutions become supersaturated with the consequentprecipitation of a number of hydrates ofzinc, manganese,and iron of which gunningite, ZISOq.H2O, is one.
AcrNowr,nocMENTs
The writers are pleased to acknowledge that the spectrographic
analyses are the contribution of G. Pattenden and w. F. white. In
addition to the quantitative *-ray fluorescenceanalysis of gunningite,G. R. Lachance kindly made many related determinatiorr". ih" writers
are indebted to R. J. Traill for his generousassistanceand careful review
of tJremanuscript. Valuable servicein various aspectsof the problem wasalso renderedby R. Delabio, R. Brown, and T. Roach.
RsrBnBNcns
Dnvar,oc_1oyrm-(1953):rnorgan'ieThermogrovi,mctrio
Anal,ysis;Elsevierpub. co.,New York, p. 276.
GmeWsHand,buchiler AnorgonischenChemie(19b6); Zinc, g, p, g4T.
Ptstontus, c^s.RLw. F. T. (1961): crystallographicpropeities of cusor.Hro andZnSOr.HzO; Acta Cryst.,t4, 684.
Monuscript rece&ted,September gB, 1961
sRozeniteis believedto
distinct from the pentahydrate,siderotil (manu\ a species
script in preparation;J. L. J.).