ECONOMIC GEOLOGY

WITI-I WHICH IS INCORPORATED

THE AMERICAN GEOLOGIST

Vo•.. VIII JUNE, x9•3 No. 4

OCCURRENCE OF COMPLEX AND LITTLE KNOWN' SULPHATES AND SULPHARSENATES AS IN UTAH3

B. S. BUTLER.

INTRODUCTION. In studyingnumerous mining districts of Utah, the writer has found that complexbasic ferric sulphates,sulpharsenates, and allied'minerals are presentin consi.derabl.equantities in the oxi- dized of the State, and in some instancesare important ore minerals. In the literature of mining geology this class of mineralshas been given scant attention, and in the districtswhere they were seenthe writer in no instancefound that the character of the mineralshad beenrecognized, though they were commonly known to be metal-bearing,which is, of course,'the important feature from the standpointof the prospectorand mine manager. Many mining men, however,as well as mineralogistsand geolo- gists, are interestedin the compositionof ores as well as in their metal content, and occasion is taken to call attention to this type of ore mineral which seemsto have been largely overlooked.

PLUMBOJAROSITE. In 19o2 Dr. W. F. Hillebrand and Prof. L. S. Penfield•' de- scribeda new mineral of the family from Cook'sPeak, aPublished with permissionof the Director of the U.S. GeologicalSurvey. ' Hillebrand, W. F., and Penfield, L. S., Am. Jour. $ci., Vol. I4, 19o2,p. 31I 3 I2 B. S. BUTLER.

N. Mex., to which they gave the name of plumbojarosite. In this minerallead replacesthe potassiumof ordinaryjarosite, the compositionformula being ?bO.3Fe2Oa'4SOa.6H20. This mineralwas not reportedagain till •9•o, when a 'second specimenwas receivedby Dr. Hillebrand, which was said to have come from American Fork district, Utah. This was ex- amined chemicallyand crystallographicallyby Drs. Hillebrand and Wrightx and foundto agreeessentially with that previously described from New Mexico. Long previousto the recognitionof the mineral in •9o2, Dr. Hillebrand• had madean analysisof a ferric sulphatefrom Lead- ville,Col&, that fromits close.correspondence to the analyses of plumbojarosite,as shownin the accompanyingtable, gives strong reasonto suspectthat it was that mineral rather than a mixture of minerals, as was then thought. Other ferric sulphatesfrom Leadville were analyzedthat containednotable amountsof potassiumand 1.ead,an,d may have been mixtures of jarosite and plumbojarosite. In •9• the wi'iter and Dr. W. T. Schallera describedthe oc- currenceof plumbojarositefrom six localitiesin Beaver County, Utah. In someof theseoccurrences the mineral was presentin sufficientquantity to be a lead ore of some importance. It becameevident that the mineral is not a mineralogicalcuriosity of rare occurrence, but an ore mineral. Since studyingthe occurrenceof plumbojarositein Beaver County,the writer hasvisited numerous other camps in Utah and hasfound that plumbojarositeis of widespreadoccurrence, being collectedfrom no lessthan •8 localities,including those men- tionedabove. In someof theseoccurrences it is presentin con- siderablequantity and, while not of high grade,is a commercial ore mineral. PhysicalProperties.--Plum'bojarosite, as seenin differenthand samples,varies considerablyin appearance. In color it ranges from a rather.light,nearly ocher yellow, to a rather dark brown. • Hillebrand,W. F., andWright, F. E., Am. ]our. $ci., Vol. 30, I9IO, p. I9X. 2,, Geologyand Mining Industryof Leadville,Colo.," I886, p. 6o6. 8Butler, B. S., and Schaller,W. T., Am. ]our. Sci.,Vol. 32, •9H, p. 4•-•-. SULPHATES AND SULPH.4RSEN.4TES IN UTAH. 313

When relatively coarselycrystalline it has a distinctlymicaceous appearance,but in the very finely crystallinematerial it appears earthyexcept on closeexamination. Wheremassive it frequently has a distinctlyschistose structure. The mineral has apparentlybeen commonlymistaken for hydrated iron oxides, and it has been assumedthat the metal

FIG. 26. Plumbojarosite,Moskow Mine, Beaver County, Utah. Magnified 45 times. valueswere presentas carbonatesor "chlorides" mixed with the hydratediron oxide. It i.susually not difficultto distinguishbetween the hydrated iron oxidesand the basicsulphates, since the oxideshave a harsh 314 B. S. BUTLER.

gritty feel whenrubbed between the fingers,while the basic sulphates,due to theirmicaceous character, have a smoothoily feel. The luster of the two is also usually distinctive,the sulphatehaving a silkyluster while the oxide is earthy. In the very finematerial this characteris lessdistinctive. Under the microscopethe crystalsin everyinstance are seento be thin hexagonalplates of a light golden-yellowcolor. The crystalsvary greatly in sizein differentoccurrences and in a single occurrence,but rarely exceed0.25 millimeterin width. In all the material examinedmicroscopically the crystalsare uniaxial, opticallynegative with strongbirefringence. The accompanying microphotograph,Fig. 26, showsthe generalcharacter of the crystals. Chemical Composition.--Threeanalyses of p!umbojarosite have been made, two from Utah and one from New Mexico. Theseare givenin the followingtable together with an analysis of oxidized material from Leadville, Co!•o.,which is not known to be a definite mineral and .the .compositionof the mineral is calculatedfrom the chemicalformula PbO'3Fe2Oa-4SOa'6H20.

ANALYSES OF PLUMBOJAROSITE.

Oxidized Mate- rial from Lower BeaverCo., Cook'sPeak, AmericanFork, WaterlooMine Utah. N. Mex. Utah. Calculated. underGray Porphyry, Leadville.

_ ß Fe2Oa ...... 42.1I 42.37 42.87 42.38 44.40 PbO ...... '... I8.32 I9.84 I8.46 I9.74 I9.5o K20Na•O...... } o.I3 o.o.2II7 o.0.52I5 ...... 37I5 SO3 ...... 27.59 27.06 27.67 28.33 25.07 H•O ...... 9.I6 9.56 Io.•4 9.55 8.99 CuO ...... 0.27 o.•o ...... CaO ...... o.oo 0.05 0.06 ...... Insol ...... 2.64 o.5I 0.40 ...... ZnO ...... 0.30 ...... SiOi ...... 36 A12Oa ...... 23 As•Oa ...... 39 P2Os ...... II C1 ...... 04 Ioo.25 1oo.•5 Ioo.37 1oo.oo 99.61 Density ...... 3.6o 3.665 ...... Lead ...... I8.3I .... : Iron ...... 29.66 ..... SULPHATES AND SULPHARSENATES IN UTAH. 315

The analysesshow a closeagreement among themselves as well as with the calculated values.

OCCURRENCES OF PLUiYIBO3AROSITE IN UTAI-I. Thefirst occurrence described from tl•e state, as already noted, was from the American Fork district. No data are available, ß however,to showthe field relationof the specimenanalyzed from that district. In Beaver County the mineral was recognizedin the ores from the following minesand prospects:Horn Silver, Hub, Moscow, Red Warrior, Harrington-Hickory and an unnamedprospect pit, and probably is present in other depositsof this section. In theseoccurrences the mineral is secondary,resul.ting from the oxidation of mixed sulphide ores. In the Red Warrior and Moscow mines, at the time of visit, it was presentin sufficient amount to be characterizedas a commercalore mineral though by no meansas importantas the carbonate,cerusite. In the Marysvaledistrict, Piute County,the mineral was found on the dump of the Deertrail mine. In the specimencollected the plumbojarositesurrounded a coreof galena. It was not observed in the mine but evidentlyresulted from the oxidationof lead and iron sulphides. Jamsite was also observed in considerable abundance in this mine. In the Clifton district, Tooele County, the mineral occurs in the Gold Hill mine of the Western Utah Co. At this locality it was observedin considerableabundance, especially in an oxidized lead ore body on the 3oo-foot tunnel level. Owing to lack of cheaptransportation facilities, there has been little production from these ores. With better transportation they would doubtlessbe of commercialgrade. In the Fish Springs district plumbojarositewas observedin considerablequantity in parts of the Utah mine, where i.t has formed in the oxidation of lead and iron sulphides. It is said that "secondclass" oxidized ore in someinstances forms a casing aroundthe high gradeore. This secondgrade is in part plumbo- jarosite. Under present transportation conditions the second 3 I6 B. S. BUTLER. gradeore cannotbe profitablyhandled, but with cheaptransporta- tion facilities it would be of commercialgrade. Plumbojarositewas also observedon the dump of the Galena mine west of the Utah mine. The mine was closed at the time of visit, but the occurrence is said to be similar to that in the Utah mine. The mineral was collected from a vein in quartzite in the north end of the Dugway Range. Plumbojarosite was collectedfrom the dump .of the Tacoma mine in the Lucin .district,Boxelder County, and from a prospect tunnel on the property of the Mineral Mountain Mining Co. In the Ophir district,Tooele County, it was found on the dump of the upper workings of the Cliff mine and from the dump of the Chloride Point and East Side tunnel workings in the Lion Hill section. In the Stockton district it was collected from the ore bins of the uppertunnel on the Honorine vein and from the dump of the Ben Harrison mine. .

BEAVERITE.

The mineral beaverire was first described from the Horn Silver mine, Beaver County,• where it occurs in the oxidized ores resultingfrom the alterationof an ore body composedprin- cipallyof sulphidesof lead, iron, zinc and copper. PhysicalProperties.--The mineral is a canary-yellowearthy lookingmaterial that canusually be easilycrushed in the fingers. Under the high power of the microscopethe material is seento be crystallizedin distincthexagonal plates. Theseare too small for accuratemeasurement of the crystal angles or determination of the opticalcharacter. The refractiveindex of the light ray vibratingperpendicular to the platesis about x.8o. Almost every.crystal contains a minute inclusionwhose char- acter has not been determined. The material analyzed appeared under the microscopeto be very pure exceptfor theseinclusions, • Butler, B. S., and Schaller,W. T., "Some Minerals from Beaver County, Utah," Am. ]our. Sci., Vol. 32, 1911, p. 418. SULPHATES AND SULPHARSENATES IN UTAH. 3•7

and it is probablethat the silicathat appearsin the analysisis due to them. Chemical Composition.•NT'hemineral is soluble in boiling hydrochloricacid, leaving the insolublematter, chiefly silica, behind.' On cooling,lead chlorideseparates out in considerable amount. The lead reactioncan also readily be obtainedwith sodiumcarbonate on charcoal. On adding ammoniain excess to the hydrochloricacid solution,the ferric iron is thrown down as a voluminousbrown precipitate, and the solution has the deep blue color indicativeof copper. By the quantitativede- termination, the presenceof a small amount of alumina was established.The insolublematter consistsmostly of silica,only a slightresidue remaining after treatmentwith hydrofluoricacid. The followingtable showsthe chemicalanalysis o.f the mineral together with the calculated analysis from the formula CuO- PbO. Fe2Os'2 SOs'4H20.

ANALYSIS AND RATIOS OF BEAVERITE.

Insol ...... lO.O5 CuO ...... 9.70 .121 ß92 or 1 PbO ...... 29.44 .132 I.OO or I

I.o7 or I Fe.•O•Al.oO• ...... 17.28 3.64 .108.036 } SOa ...... 21.32 .266 2.01 or 2 H20 ...... 9.02 .5Ol 3.80 or 4 (= 4x .95). lOO.45

The ratios agreewell with the formula CuO.PbO.FE•Oa.2SOs-4H•O, in whichthe copperand lead are assumedto be presentin equal molecularamounts, and in whicha little ferric iron is replaced by alumina. A comparisonof the analysiswith the insolublematter de- ductedand reducedto Ioo per cent.,with the valuescalculated for the formula last given, is shownbelow. • The material was examinedchemically by Dr. W. T. Schaller. 318 B. S. BUTLER.

COMPARISON OF ANALYSIS WITH CALCULATED VALUES.

Analysis. Calculated. CuO ...... Io.74 I •.7o PbO ...... 3:•.5o 3:•.8o Fe20• ...... I9. I3 •7.6• AI•Oa ...... 4.03 3.75 SOs ...... 9.3.60 9.3.54 H20 ...... •o.oo Io.6o

I00.00 I00.00

Copper ...... 9.34 Lead ...... 30.44 Iron ......

A mineral of similar compositionand character occurs in considerable amount in the oxidized ores of the Alta Consolidated mine in the Alta district. At the time of visit ore that contained this mineralas an importantconstituent was being taken out for' shipment. A mineralcorresponding to beaverirein physicaland chemical propertieswas collectedfrom the dumpsof the Hidden Treasure mine,Ophir district,and from the Paymastermine in the Beaver Dam Mountains,Washington County.

BEUDANTITE AND ALLIED MINERALS. Under the name beudantite are included a series of minerals of somewhatvariable and uncertaincomposition, but essentially sulpharsenatesor sulphphosphatesof lead and ferric iron with minor quantitiesof other constituents,especially copper, which may reach several per cent. The arsenateshave been commonly called beudantite, while the phosphateshave been designatedcorkire, though this division doesnot appearto have been followedby all writers. So far asthe writer is aware,the firstlocality on thiscontinent from which a member of this series was described,was from Beaver County, Utah.• In Beaver County, the mineral cotkite occursin the Harrington-Hickory and Wild Bill minesin the Star districtand probablyin other minesof that region. The mineralas seen in thehand specimen is a lightgreen earthy • Op. cit., p. 423. SULPHATES AND SULPHARSENATES IN UTAH. 3 I9

looking material which when crushedin the fingershas a gritty feel like fine sand. Under the microscopeit is found to be well crystallized,the larger crystalsbeing o. • 5 millimeter in diameter. The crystalsare golden yellow in color and have the general appearanceof being a combinationof the cubeand octahedron. They are rather stronglybirefringent, however, and are probably hexagonal rhombohedral. 'Coi-kite is readily solublein boiling hydrochloricacid from whichsolution lead chlorideseparates-out in quantityon cooling. Th• solution contains,besides lead, abundant ferric iron and the sulphateand phosphateradicals. Qualitative testsfailed to'show the'presence of any arsenic,and only a mere trace of copper'is presentin the corkite from thesemines. Heated in a closedtube, the mineral darkensand givesoff water. In both of the mines mentionedthe original ores were' a replacementof limestonenear an intrusive rock and considerable apatite and contact silicates were formed with' the metallic sulphides,mainly pyrite, galena, sphalerite,and chalco.pyrite. The corkiteis a secondarymineral resulting from 'thealteration of theseores; the phosphatedou. btless ' being derivedfrom the apatiteand the metalliccontent from the sulphides. A mineral having physicalproperties similar to those men- tionedabove but containingmainly arsenic in placeof phosphate, was collectedfrom severalprospects near the southend of Clifton Mountainin the Clifton d•istrict,Tooele County. The oresoccur as replacementveins in limestone. The beudantite is an oxida- tionproduct and since the mines have been but slightly developed, the primary minerals from which it was derived are not known though it is safe to infer that arsenidesor sulpharsenideswere present. Similar minerals were collectedfrom the Black Warrior and Paymastermines, Washington County. There canbe little doubtthat mineralsof this typeare presentin manyother mines of the state. Numerouscomplex arsenates occur in the Tintid district,but thosedo not containferric iron as an importantconstituent. • Tower,G. W., andSmith, G. 0., NineteenthAnn. Rept. U.S. Geol.Survey, Pt. 3, p. 69i. 32O B. S. BUTLER.

JAROSITE. Jarosite,K20'3Fe2Oa'4SOa'6H20, is presentin many of the mines of the state and in several has been noted in abundance. It has been previouslydescribed from the Tintic district,• and from the Mercur district? The writer has noted the mineral in particular abundancein the Deertrail mine in the Marysvale district where it is closely associatedw.ith sericitic muscovite, from the Dixie .coppermine in WashingtonCounty, from a prospectin the Detroit districtwhere it has 'been mined to a limited extent for flux in a local smelter, and from severalmines in Beaver County. It is also present with allied minerals, such as plumbojarositein other localities. In fact thesetwo minerals,jarosite and plumbojarosite,can be readily detectedonly by chemicalmeans. There is no doubtthat it is one of the rather common minerals in the ores of the state. Utahite, 3Fe2Oa.3SOa.4H•O, occurs in the Tintic district,• and is probablypresent in other districts. It rather closelyresembles jarosite in its physicalproperties. In the material that the writer has collected he has not found utahiteand consequentlyis inclinedto considerit of lessfrequent occurrencethan jarosite. It is frequentlynot possible to collect these minerals in Suffi- cient purity to permit of a careful chemicaldetermination, and there is little doubt that there are numerous minerals allied to thesein compositionin the ores of the state. In the lower portionof the oxidized"capping" of the Bingham disseminatedcopper ores, a mineral or minerals occur that are similar in many physicalproperties to beaverire. This couldnot be separatedin sufficientpurity to permit of careful chemical examination,but it givesa strongreaction for sulphateand ferric iron and someof the material testedcontained copper in notable amounts,and sinceno other coppermineral was recognizedthis mineral is believedto be copperbearing. It containedno lead. a Op. cit., p. 702. 2 S,purr, J. E., "Economic Geology of the Mercur Mining District, Utah," Sixteenth Ann. Rept. U.S. Geol. Survey, Pt. 2, p. 44o. 8Nineteenth Ann. Rept. U.S. Geol. Survey, Pt. 3, p. 7o3. SULPHATES AND SULPHARSENATES IN UTAH. 321

Other material similar in appearanceshowed no copper,or but a trace.

OCCURRENCE OF THE COMPLEX FERRIC SULPHATES AND / ARSENATES. • All the mineralsdescribed occur in the oxidizedportion of the veins. They are not presentin the outcrop,though they have beenfound only a shortdistance below the surface. They have resultedfrom the oxidationof mixed sulphideand arsenideores and in someinstances appear to occupyessentially the positionof the primary ores; in other instancesthe occurrencesuggests the formationof the mineralsby the actionof ferric solutionson sul- phidesor otherminerals, examples being cores of galenaenclosed in plumbojarositeand jarosite occurringwith sericiticmuscovite where the potassiumappears to have been derived from the muscovite. As already noted, the minerals are not stable under surface conditions,and therecan be no doubtthat they are lessstable than the lesscomplex carbonates and oxidesand that theybreak down to form theseminerals. In fact numerousexamples have been observedwhere the 'minerals were altering to hydrousiron oxide, and probablyto carbonatesof lead, etc., thoughthe metalsother than iron in some instances at least seem to have been removed when the mineral broke down. It is evident,therefore, that theserelatively complex compounds representa stagein theprocess of oxidationbetween the sulphides andthe moresimple oxide and carbonatecompounds, The sim- pler sulphates,as anglesite,are doubtlessformed to someextent in the alterationof theseminerals, though all the metallicsul- phatesare relatively unstable. For example,anglesite commonly occursas an intermediatestage in the alterationof galenato cerusite,x and linarite has been noted in a similar relation to more complexsulphide ores in the Horn Silvermine, Beaver County, andbrochanthite also occurs as an intermediatestage in thealter- ation of corellite and chalcocite to carbonates. •Boutwell,J. M., '"Geologyand Ore Depositsof the Park City District, Utah," Prof. PaperU.S. Geol.Survey No. 77, P. •4. 322 B. S. BUTLER.

In the breakingdown of the complexferric sulphates,hydrous iron oxidesand solubleor insolublesulphates may be formed, or sulphuricacid may be liberatedthat will act on otherminerals to form sulphates. It is apparentthat the formationof the complexferric sulphates simplydelays the oxidationprocess while they are passingfrom the zone in which they were formed and are stableto a zone where they becomeunstable and break down. The ferric sulphatesand arsenateshave been observedmost frequently in the relatively arid regionswhich suggeststhat an arid climatemay be especiallyfavorable to the formationof such minerals. Their presencein considerableabundance in the Alta district, which has a large rainfall, and possiblyat Leadville, Colo.,throws serious doubt on this suggestionand more observa- tionsare necessarybefore a generalizationconcerning the condi- tionsunder whichthey form will be warranted. Onegeneralization is,however, warranted, namely, that all yel- low andbrown more or lessearthy materials are not limonite,and if suchcontain metals other than iron they are not necessarily present as carbonatesor "chlorides." The geologistor mineralogistvisiting a mine for a few days is notlikely to getthe best mineral specimen that the mine affords, but if thosein chargeof the mineoperations will preservesuch materialand turn it overto someoneinterested in themineralogy of ores,we maysoon have much more data concerning these in- terestingtypes of minerals,which in the minesof Utah, at least, aremuch more important than is generallyrecognized.