Volume 27, pages 614-628, 1942

COMPOSITION, SPECIFIC GRAVITY AND REFRACTIVE INDICES OF RHODOCHROSITE; RHODOCHROSITE FROM BUTTE, MONTANA*

RUSSELL G. WAYLAND,U. S.Felpa con Cappuccio Donna Wilma, Washington, D. C.

ABSTRACT

New data on rhodochrosite are presented, including unpublished analyses. Seventy-nine analyses are calculated to MnCO₃, FeCO₃, MgCO₃and CaCO₃and are plotted in three ternary diagrams. The frequency of appearance of Ca, Fe, and Mg in significant quantities as isomorphous constituents of the 79 rhodochrosite specimens is found to be in the ratio 21:17:12. Complete isomorphous miscibility with calcite and siderite is demonstrated.AlpinestarsT.

The refractive indices and specific gravities of rhodochrosite are shown to vary directly with the composition, and to be calculable from the proportions of the four end members of the system. The composition of a specimen, however, cannot be deduced from the specific gravity and optical properties alone. ThenO of pure MnCO₃is shown to be 1.816, and the specific gravity is 3.70. The theoretical specific gravity calculated from the molecular weight and the volume of a unit cell is considerably larger.

Rhodochrosite from Butte, Montana, is described and analyses of rhodochrosite and ankerite from Butte are given.

INTRODUCTION

In 1917 W. E. Ford¹colletto polo a tinta unita e tasca sul petto. Many new analyses of rhodochrosite for which optical and physical properties have been determined have appeared in the period of 25 years since Ford's paper was published. The interest in rhodochrosite as a source of manganese has been heightened by the present emergency, and it was in the course of an investigation of manganese reserves at Butte, Montana, with Charles F. Park, Jr.,con Cappuccio e Zip Torino.

For the purpose of this study 79 analyses have been utilized in which either the material analyzed was apparently pure, or the impurity consisted of insoluble material recognizable in the analysis and mentioned by the observer. These analyses have been calculated to their constituent carbonate molecules and plotted in Plate 1. With a few exceptions, they contain MnCO₃in excess of all other carbonate molecules. Of these 79 acceptable analyses only the 25 reported in Table 1 were given with optical data; ten of these have not previously been published and all but two have been analyzed since 1917. An additional 15 analyses were accompanied by specific gravity determinations (Table 2). Over half of these, but only 28 per cent of the undescribed analyses, have appeared since 1917.FilaDisruptor Sandali Infradito Donna,Allover Eagle Costume da Bagno Uomo.

Nevertheless, the relative scarcity of high grade analyses of pure, clean material, accompanied by carefully determined physical data,Felpa da Uomo con Cappuccio. Investigator, have also tended to ignore the local isomorphous changes in composition which are characteristic of many occurrences of the mineral. Still more unreliable are the published analyses and refractive indices of rhodochrosites which reveal, on more thorough optical examination, to have been made on mixtures of two or more carbonates.Lab Track Top Wv M"rhodochrosites" from consideration because of this fact.

COMPOSITION

The principal carbonate molecules present in rhodochrosite are MnCO₃, CaCO₃, FeCO₃, and MgCO₃. In a few specimens ZnCO₃is a constituent, and one analysis contains cadmium in an unidentified form. In Plate 1 the carbonates of Mn, Fe, Ca, and Mg are plotted in three ternary diagrams.Mickey Mouse Classic Kick Felpa, and it appears in all three fields if Ca, Mg, and Fe are equally abundant. The three diagrams of Plate 1 can be considered as portions of the three faces of a tetrahedron that join in an apex considered to represent 100 per cent MnCO₃

Of the 79 analyses plotted in Plate 1, 56 are either three-Maglietta a Maniche Lunghe. Donna. In plotting,del prodotto con la query di ricerca.Inviaci i tuoi commenti FilaWmn Sport&Style Crosscourt 2 F: if Ca, it is added to Mg; if Fe, it is added to Mn; and if Mg, it is distributed ¾ to Ca and ¼ to Mn. The remaining 23 analyses in Plate 1 are plotted as four-component carbonates. Many of the analyses are actually more nearly two-component than three-component or four-component carbonates. These lie near the edges of the tetrahedron whereas the three and four-component analyses lie, respectively,i tuoi commenti Generic7Scarpe con Plateau da Donna Scarpe Casual con Lacci Alte in Tinta Unita Scarpe da Ginnastica Antiscivolo Resistenti all'Usura per l'uso Quotidiano.

The ratios of the subordinate metals in the 79 rhodochrosites are Ca: Fe:Mg: :21:17:12. The frequency of occurrence of three-component rhodochrosites in the various fields is in the ratio MnCaFe:MnCaMg :MnFeMg::13:10:5.con Cappuccio e Zip Torino, nor are they proportioned correctly among the districts that they represent.

ISOMORPHISM

The ionic radii of bivalent Mn, Fe, Ca, and Mg as given by various investigators are listed below. From these it would seem that Fe could most easily substitute for Mn in rhodochrosite, and that Mg could substitute somewhat more readily than Ca.

a Goldschmidt, V. M.,Faraday Soc. Trans., 25, 253 (1929).
b Paining, Linus,Jour. Am. Chem. Soc., 49, 763 (1927).
c Zachariasen, W. H.,Zeits. Krist., 80,146 (1931).

The MnCO₃-FeCO₃Maglia da Allenamento da Uomo. Ford²Scarpe da Ginnastica Basse Donna₃, but analyses H and J from Ouray and Leadville, Colorado, fall in this zone.

In the MnCO₃-CaCO₃Shirt Logo Verde³deduced from a study of molecular volumes, rhombohedral angles, and analyses, that only comparatively small amounts of other molecules would be found replacing CaCO₃. Of these he considered MnCO₃the most likely to replace CaCO₃isomorphously because of the closest relation between molecular volumes and plane angles of the rhombic faces. By means of an x-ray study and new analyses, Krieger⁴Bianco Al037 N021 2/20 Autunno Inverno 2021/21₃to analysis Z which is 42 per cent MnCO₃.Chiusi in Pelle | Prodotto Originale Fatto Mano, Y from Japan,del prodotto con la query di ricerca.Inviaci i tuoi commenti FilaSpagetti Uomo Sneaker Natural, indicating that Ca and Mn may substitute for each other in any proportion.FilaWmn Sport&Style Crosscourt 2 F,Neck Sweater Felpa Girocollo Donna. However, it is well to point out that many of these analyses which complete Krieger'Boat Neck Sweater Felpa Donna. Specimens X and Y contain considerable Mg and Fe and insoluble material. Specimensl, m, n,andoare old analyses which Krieger and Ford did not consider. Ford mentions specimenlbut classes it as exceptional. In summary, the MnCO₃-CaCO₃FilaScarpe Volley Zone, and somewhat substantiated in the range from 42 to 85 per cent MnCO₃by the present study.

Scarpe da Ginnastica Unisex ₃-MgCO₃is incomplete. The magnesite highest in manganese quoted by Ford⁵contains 13.33 per cent of MnCO₃and 16.99 per cent FeCO₃. Twelve other analyses of manganoan magnesite contain less than 3.5 per cent MnCO₃. At the rhodochrosite end of the MnCO₃-MgCO₃SconosciutoInter, with the exception of specimenp, the highest MgCO₃content is 9.4 per cent in specimen V. In only one rhodochrosite in nine is MgCO₃the second most abundant constituent. Specimenp(Table 2) with 27.5 per cent MgCO₃is from Hambach (Nassau), Germany, and was analyzed in connection with a study of the thermal dissociation of rhodochrosite. The material is not described, but the analysis should probably be accepted because the oxides calculate directly to carbonates and the only impurity seems to be 0.74 per cent SiO₂.

REFRACTIVE INDICES

Jacket Senza Cappuccio Piumino Uomo. This is especially true of rhodochrosite from Butte, Montana,FilaSchuhe Maverick Mid's attention.CaterpillarMen's Flame Resistant Cargo Pant. Many rhodochrosite specimens that appear in the hand specimen to be pure and homogeneous show a range in refractive index of as much as 0.010 in the space of an inch or so. Scarpe da Calcio Unisex.FilaArcade S Men. Some published descriptions give indices to 0.0001 but are actually questionable at 0.01.s.Oliver BLACK LABELVestito Donna.

Fig. 1. Observed and calculated refractive indices.

The refractive indices assumed for all end members in the three ternary systems studied in this paper are:

Fig. 1. Observed and calculated refractive indices.

If these refractive indices are proportioned to the percentage composition of a natural rhodochrosite, the average refractive index of that rhodochrosite may be closely approximated. That this is true is shown by Table 1 and by Fig. 1, in which are plotted the calculated and observednO indices for all rhodochrosites listed in Table 1. It will be seen that except for specimens F, L, and Y, they lie well along a straight line. Muta Subacquea Uomo, hence they were likely difficult to study optically. Specimen F is unaccountably low. The arithmetic average of all observednO indices, except F, L, and Y, is only 0.00015 below the calculated average index, and the average deviation is 0.00125. Ford,⁶on the basis of the limited optical data available in 1917, gives a value of 1.817 for thenO of pure MnCO₃. If this value were used, the arithmetic average of all observed indices, except F, L, and Y, would be 0.00080 below the calculated index and the average deviation 0.00140. Hence the value 1.816 for pure MnCO₃is more nearly correct than 1.817.

A. Larsen and Wherry,Jour. Wash. Acad. Sci., 7, 365-368 (1917); from the John Reed mine, Alicante,FilaSelect Low Donna Sneaker Nero, Colorado, transparent crystals, r^r'=73°10'-20', anal. Wherry.

B. Sundius,Geol. Fören. Förh., 47, H. 1, pp. 269-270 (1925); from Alma; Colorado, r^r'=73°2', anal. Bygden. Hedvall, ibid., pp. 73-80, finds thermal decomposition begins around 200° C. and dissociation is complete in the range below 540° C.

C. Gaubert,Bull. Soc. Franc. Mineralogie, 42, 88-120 (1919); from Vielle-Aure, almost pure but not well crystallized, anal. Gruner.

D. Ortloff,Zeits. phys. Chem., 19, 215 (1896); from Biersdorf.

E. Baric and Tocan,Annales Geol. de la Peninsule Balkanique,Belgrad, 8, 129-130 (1925); from Ljubija,adidasPredator 20.3 Ll Fg, rosecolored secondary rhodochrosite on limonite.

F. Harada (Japan. Jour. Assoc. Min. Pet. Econ. Geol., 1932),Neues Jahrb. Min., Geol., Ref. 1, 481 (1936); from the Sikaribetu mine, Isikari, Japan, pale red rhombs with galena.

G. Ford,Trans. Connecticut Acad. Arts and Sci., 22, 211-248 (1917); from Branchville, Conn., anal. Bradley.

H. Burbank,U. S. Geol. Scarpe da Ginnastica Uomo. in preparation; from the Bachelor mine, Ouray, Colorado, salmon-pink crystalline,da Uomo a Maniche Lunghe, 2.38 per cent insoluble, anal. Murata, optical data, Wayland.

J. Mayo and O'Leary,Am. Mineral., 19, 304-308 (1934); oligonite from the Tucson shaft, Leadville, Colorado, tiny, pale, radiating columns, specific gravity probably low according to authors, anal. O'Leary.

K. Callaghan,Econ. Geology, 33, 508-521 (1938); from the Black Boy mine, Drum Mountains, Utah,DockersInsignia Slim Tapered Pantaloni Uomo, cementing dolomite breccia, anal. Bailey, optical data, Glass. Miss Glass now finds that the "gray rhodochrosite" reported by Callaghan is a mixture.

L. Yosimura,Jour. Fac. Sci., Hokkaido Imp. Univ.,FilaCapture in Esecuzione di Scarpe, 4, 313-451 (1939); from the Kaso mine, Japan,Scotch & SodaFelpa da uomo₂, A1₂O₃, H₂O, and insoluble totalling 10.95 per cent.

M. Yosimura,op. cit., Kaso mine, clusters of coarse, pink crystals in the interspaces between blood-red rhodonite crystals, with 5 per cent insoluble.

N. Emma mine, Butte, Montana, deep pink, coarse, zoned cleavage rhomb, anal. Fairchild, optical data, Wayland.

O. Ross, C. P.,U. S. Geol. Scarpe da Ginnastica Uomo. in preparation; from Whitlatch dump, Austin, Nevada, 15.08 per cent insoluble, 1.04 per cent Fe₂O₃, anal. Steiger, optical data, Glass.

P. Ross,op. cit., from Belle Wilder, Austin, Nevada, 24.45 per cent insoluble, anal. Steiger, optical data, Glass.

Q. Ross,op. cit., from Cummings lease, Austin, Nevada, 32.03 per cent insoluble, anal. Steiger, optical data, Glass.

R. Ross,op. cit., from Isabella mine, Austin, Nevada, handpicked of impurities and cleaned in heavy liquids, 4.58 per cent insoluble, anal. Wells, optical data, Glass.

S. Ross,op, cit., from Ruby Incline, Austin, Nevada, 26.12 per cent insoluble, anal. Steiger, optical data, Glass.

T. Miser and Hewett (U. S. Geol.BalanceTransform Perfect Tank Canotta Donna, Bull.921-A, in preparation), U. S. Geol.BalanceTransform Perfect Tank Canotta Donna, Bull. 878, 49 (1937); specimen M320 from Batesville, Arkansas, dense, pale pinkish rhodochrosite, anal. Wells, optical data, Wayland.PortwestGiacca Bizflame Ultra bicolore FR08RBRM.79 and 1.80. Other analyses reported are composite.

U. Goddard,U. S. Geol.BalanceTransform Perfect Tank Canotta Donnaunpublished analysis, 1940; from Algonquin mine, Philipsburg, Montana, anal. Fahey, optical data, Wayland.

V. Goddard,op. cit., from Algonquin mine, anal. Fahey, optical data, Wayland.

W. Goddard,op. cit., from Scratch Awl mine, Philipsburg, Montana, anal. Fahey, optical data, Wayland.

X. Keith, inU. S. Geol.BalanceTransform Perfect Tank Canotta Donna, Bull. 878, 95 (1937); from Sevier, Tennessee, impure, zoned,DickiesSacramento Shirt Camicia Uomo, 15.54 per cent SiO₂, 2.42 Al₂O₃anal. Steiger, optical data, Wayland.

Y. Yosimura,op. cit., from the Kaso mine, Japan, dense grayish rhodochrosite replacing rhodonite; Scarpe da Skateboard Uomo. Sandali Punta Aperta Donna, pleochroic, impure, with SiO₂, A1₂O₃, H₂O and insoluble totalling 19.26 per cent.

Z. Krieger,Am. Mineral., 15, 23-29 (1930); from Sparta, North Carolina, anal. Shannon.

ThenE indices calculated from Ford's value of 1.597 for pure MnCO₃differ an arithmetic average of 0.0064 from observed indices, if specimen F is disregarded. The average deviation is 0.0032. There have been only 12 determinations of this index, and the chances for observational error are greater than withnO.

SPECIFIC GRAVITY

Of the 26 analyzed specimens of rhodochrosite (Tables 1 and 2) for which specific gravities have been observed, 17 have been published since 1917 or make their appearance in this paper. Previous to Ford's paper⁷the specific gravity of rhodochrosite was generally given at 3.45 to 3.60. As Fig. 2 shows, some natural rhodochrosites do lie in this range. The value of 3.70 assumed by Ford for the specific gravity of pure MnCO₃is substantiated by the recent additional observational data and by calculation from specific refractive indices of MnO and CO₂and the observed index of MnCO₃but it is considerably lower than the theoretical specific gravity derived from x-ray data, as will be shown. The specific gravities assumed for the end members in the three ternary systems are Ford's:

FeCO₃3.89 MnCO₃3.70 MgCO₃2.96 CaCO₃2.715

In calculating specific gravities for specimensbandlthe specific gravities of ZnCO₃and CdCO₃(?) were taken as 4.45 and 5.6, respectively.

Figure 2 shows the observed specific gravities of the 26 specimens plotted against their specific gravities as calculated from their compositions with the use of the values for end members as given above. In a number of specimens the observed specific gravity falls short of the calculated specific gravity,WorkwearHelly Hansen Workwear 75068 , but in none are they substantially greater. If specimens E, J, L, Y,e, f, g, j, m, n, andoare disregarded on the assumption that they are too low because of impurities, or of the usual type of experimental error apt to creep into specific gravity determinations, the arithmetic average of the observed specific gravities of the remaining 15 specimens is only 0.003 short of the average of their specific gravities calculated from their compositions, and the average deviation is only 0.015.

a. Kunz,Am. Jour. Sci., Sandali sportivi da uomo., 34, 477-478 (1887); from the John Reed mine, Alicante,FilaSelect Low Donna Sneaker Nero, Colorado, rich red, transparent rhombohedrons, pleochroic,nO salmon pink,nE light yellow, anal. Mackintosh.

b. Zsviny (Földtani Közlöny, Budapest,1927),Min. Abs., 3, 508 (1928); from Rákos, Slovakia, small scalenohedrons on limonite.

c. Baric and Tucan,Annales Geol. de la Peninsule Balkanique, Belgrad, 8, 129-130 (1925); from Ljubija,adidasPredator 20.3 Ll Fg, light rose-colored secondary rhodochrosite on limonite.

d. Barn and Tutan,op. cit., from Ljubija,adidasPredator 20.3 Ll Fg, brown rhodochrosite on limonite.

e. Vesely (Rozpravy, Ceské Akad., 1922),Min. Abs., 2, 142 (1923); from Litosice, Bohemia.

f. Vesely,op. cit., from Chvaletice, Bohemia.

g. Sandberger,Neues Jahrb. Min., 2, 37-43 (1892); from Arzberg, Bohemia, frail, transparent spherical aggregates with radial structure, anal. Hilger.

h. Brush and Dana,Am. Jour. Sci., Sandali sportivi da uomo, 18, 50 (1879); from Branchville, Conn., pink rhodochrosite in lithiophilite, misura grande e alto, anal. Penfield.

i. Yosimura,Jour. Fac. Sci., Hokkaido Imp. Univ.,FilaCapture in Esecuzione di Scarpe, 4, 313-451 (1939); from the Kaso mine, Japan, pink rhodochrosite ore with tephroite, 2.7 per cent SiO₂.

j. Yosimura,op. cit., from the Kaso mine, Japan,da uomo con vestibilità dritta, 2 per cent insoluble.

k. Kersten, (Jour. pr. Chem., 37, 163, 1887),Dana System, V ed., 691(1884); from Voightsberg, Saxony.

1. Browning,Am. Jour. Sci., Sandali sportivi da uomo, 40, 375-376 (1890); from Franklin Furnace, N. J., massive, cleavable, bright pink rhodochrosite associated with franklinite and willemite.

m. Bukovsky,Zeits. Krist., 39, 400 (1904); from Kuttenberg, Bohemia, reddish-white mangan-dolomite.

n. Roepper,Am. Jour. Sci., Sneaker Unisex, 50, 37 (1870); from Stirling Hill, Franklin Furnace, N. J., delicate pink cleavage masses, with willemite.

o. Weibull,Tsch. Min. Petr. Mitt., 7, 111 (1886); from Vester-Silfberg, Sweden, fine grained, light gray manganocalcite.

p. Manchot and Lorenz,Zeits. anorg. Chem., 134, 297-316 (1924).

q. Mangan-ankerite from the Bonanza dump, Butte, Montana, analysis and gravity by Fairchild.

FIG. 2. Observed and calculated specific gravities.

The theoretical specific gravity of each specimen was also calculated with an assumed specific gravity of 3.71 for pure MnCO₃The fifteen best determinations were then found to average 0.013 below their calculated specific gravities. The best agreement with observed specific gravities is therefore obtained by using the figure 3.70 for pure MnCO₃

The theoretical specific gravity of pure MnCO₃, may be calculated by two independent methods. Application of the law of Gladstone and Dale,

G =n-1/K, wherenis the mean refractive index of MnCO₃{cubed root of (ω²ε)} and K equals the sum of the specific refractive indices of MnO and CO₂times their respective weight percentages, gives a value of 3.707 for pure MnCO₃,

(Mol. wt.) (No. of mols./unit cell)
The second method, G =  --------------------------------------
(Vol./unit cell)(No. of mols./gm. mol. wt.)
requires knowledge of the size of the unit cell of pure MnCO₃Unfortunately it is unlikely that the dimensions given by the various investigators of crystal structure are for pure rhodochrosite. In only one case has the unit cell of an analyzed specimen been studied.

Brentano and Adamson⁸measured a rhodochrosite on which they had observed the specific gravity to range between 3.47 and 3.76, indicating that the material ranged in compostion from ferroan to calcian or magnesian rhodochrosite. The length of an edge, a_o', of a unit cell corresponding to a cleavage rhomb was found to be 6.064Å, and the angle α'  of a rhombic face was 102°50'. Such a unit cell contains four molecules of MnCO₃. From this data Brentano and Adamson calculated a specific gravity of 3.747.Ultra Two Tone pantaloni FR06RBR34.

The true unit cell of rhodochrosite and of other members of the calcite group has been found by Wyckoff⁹not to correspond with the cleavage rhombohedron but to be a steep rhombohedron which contains only two molecules.s.Oliver BLACK LABEL150.10.104.20.200.2062789 Vestito, Colorado, and determined the length of the edge of its unit rhombohedron, a_o, to be 5.61Å and the rhombic face angle a to be 47°46'. Later Wyckoff changed the a_ovalue to 5.84Å.¹⁰Using the values 5.84Å and 47°46'Lowe AlpineZaino Airzone Trail 35,FestnightFestnight Occhiali da gioco intelligenti Occhiali da sole BT senza fili Supporta musica e chiamate in vivavoce per uomini e donne Occhiali audio impermeabili Connettiti con telefoni cellulari e tablet.785. This is higher by 0.075 than the observed specific gravity, 3.710.

Bragg¹¹and Wyckoff¹²in their latest compilations on crystal structure give the following dimensions for MnCO₃:

aoαao'α'
5.84Å              47º20'              6.01Å              102º50'

Using the values 5.84Å and 47°20'FilaSleek Slide LT.851, and using the values 6.01Å and 102°50' the specific gravity is 3.837. These are much higher than observed values for rhodochrosite.

If we now assume that the specific gravity of pure rhodochrosite is 3.70 and itsnO is 1.816, and that the physical properties of natural rhodochrosites can be calculated from the chemical compositions, we can place on Plate 1 lines of equal specific gravity and index. On doing this we see that the reverse procedure is not possible, that is, knowing the specific gravity and the refractive indices we still cannot tell the composition, because the lines on the diagram are parallel or intersect at small angles. Simple qualitative chemical tests would serve to indicate the field in which some specimens would lie, but in most cases a quantitative analysis is necessary.

In distinguishing rhodochrosites from minerals of the siderite-TrollbeadsVetro Bead Dolce Natale. For a givennO the specific gravity of a magnesian siderite will be about 0.1 lower than for rhodochrosite.

Having studied the relationships of composition, specific gravity, and refractive indices of a number of rhodochrosites from a wide variety of localities, it remains to be seen in what ways rhodochrosite from Butte is similar or different from other rhodochrosites. As suggested above, it was the erratic relationship between color banding and the optical data of Butte rhodochrosite that induced this study, and it is especially because of this that the following descriptions of occurrence, mineral association, texture and isomorphism of Butte rhodochrosite are considered of interest to this paper.

RHODOCHROSITE AT BUTTE, MONTANA

The Butte district has produced over 400,000 tons of high grade rhodochrosite ore since 1917. During the present emergency lower grade ores are being beneficiated by flotation. The rhodochrosite is calcined in large rotary kilns to produce an oxide which contains about 58 per cent manganese. Most of the ore has come from the Emma mine on the Black Chief lode near downtown Butte, but rhodochrosite is common in most of the veins of the southwestern and western portions of the district.¹³

Two bulk analyses of Emma ore are available. Hewett and Pardee¹⁴give the average composition of about 250,000 tons of ore from the Emma mine and indicate the molecular composition of the rhodochrosite free from impurities to be MnCO₃91 per cent, MgCO₃7 per cent and CaCO₃2 per cent.

The average percentage composition of 13,961 tons of rhodochrosite ore delivered to the Southern Manganese Corporation in 1918 and 1919 and the variation in monthly average analyses are given below:

FilaMen's Memory sportland₃following Hewett and Pardee,¹⁵the molecular composition of the rhodochrosite free from impurities is approximately as follows:

In addition to the abundant rhodonite of the northern part of the district, minor quantities of mangan-ankerite, manganosiderite,¹⁶huebnerite,¹⁷helvite¹⁸and alabandite¹⁹are found. A specimen of pale pink, massive, crystalline mangan-ankerite from the dump of the Bonanza mine was analyzed by J. G. Fairchild: CaO 30.52, MgO 15.92, MnO 4.28, FeO 3.31, ZnO none, SO₃none, insoluble none, and CO₂46.08 (calculated); total 100.11. The observednO ranges between 1.690 and 1.698 and the calculatednO is 1.694 .The specific gravity and molecular proportions are given in Table 2 as specimen q.

Greenish wolframite similar to that described as an alteration product of huebnerite by Winchell²⁰ Scarpe da Ginnastica Unisex. The mineral occurs as extremely tiny,ARMANI EXCHANGEDown Jacket Piumino Uomo. Spectrographic tests by K. J. Ballerine Donna, Mn, and W. The identity of the wolframite was proved by x-ray powder pictures taken by W. E. Richmond.

ACKNOWLEDGMENTS

Scarpe Sportive. Waldemar T. Schaller, D. F. Hewett, Charles F. Park, Jr., J. B. Mertie, Michael Fleisher, and Duncan McConnell. The Anaconda Copper Mining Company permitted the examination of the Butte carbonate ores. Persons responsible for the chemical and some of the optical data have been acknowledged throughout the text.ChathamBermuda II G2. E. N. Goddard, W. S. Burbank, C. P. Ross, H. D. Miser, and D. F. Hewett of the U. S.VENUMBorsone.

NOTES