BRADLEYI'TE,

A NEW MINERAL, SODIUM PHOSPHATE.
MAGNESIUM CARBONATEI

Josorn J. Fauov,
GeologicalSurley, Washington,D. C,,with
X-ray Analysis
byGBoncr TuNrrr,
Geop hysical Laboratory, CarnegieI nst,itutionoJ W ashington,
Washington,D. C.
Atsrnact

identification.

INrnooucrroN
A secondnew mineral has been found in the oil shale of the drill coreof the John Hay Jr. Well No. 1 from which shortite,2Na2Ca2(COe)a,wasobtained and recently described.This well, in the Green River formation,is on government land about 20 miles west of the city of Green River,
Sweetwater county, wyoming. Because of the unusual association ofminerals found in these shales,the writer visited the area in the summerof 1939and through the courtesy of the Mountain Fuel Supply Company
was able to obtain about 500 feet of the drill core containing the saline
minerals in the shale. This is now being examined critically and carefully
logged throughout its length.
Bradleyite was found as a layer an inch thick at a depth ol 1342,10,,.
The other saline minerals in the drill core so far determined are trona,
shortite, pirssonite, gaylussite, bromlite, and northupite. Montmorillonite, qtartz, dolomite, and pyrite are also present. The new mineral isnamed bradleyite in honor of Dr. Wilmot H. Bradley of the GeologicalSurvey, U. S. Department of the fnterior, whose many years of productive geologicinvestigation in this area well merit this recognition.
I Published by permissionof the Director, Geological Survey, U. S. Department of theInterior, Washington, D C.
2 Fahey,J. J., Shortite, a new carbonate of sodium and calcium:,4 m. Mineral.,24r 574_s18(1e3e).

646

BRADLEYITE, A NEW MINERAL

647

The writer wishes to express his thanks to Dr. George Tunell of theGeophysicalLaboratory, Washington, D. C., who contributed the sectiono\ *-ray analysis.
Occunnnxcp
The one-inch layer of very fine grained bradleyite contains about 30
per cent of much coarser shortite, and 10 per cent of clay (montmorilIonite). The clay contains organic matter which yields oil when heated ina closedtube. A thin section shows that the crystals of shortite have been
partly replaced by bradleyite. Above the bradleyite, the core consists
essentially of shortite and northupite with a little clay; below the bradleyite, it consists of brown clay which contains about 40 per cent ofshortite and 20 per cent of northupite. In both parts of the core thenorthupite is later than the shortite.
PHvsrcar PnopBnrrps
The bradleyite is extremely fine grained. Hardly any grain, extinguishing as a unit, as seen in thin section under high magnification, is morethan 0.002 mm. across. The birefringence is strong. Only the extreme
indices of refraction could be measured,a being about 1.49 and 7 about
1.56,hencethe birefringenceis about 0.07.
The mean index of refraction of the clay is about 1.555, that of thebradleyite mixed with clay is 1.530.Taking into consideration the relative proportions of bradleyite and clay in the mixture (85 and 15 percent respectively), by computation the mean index of bradleyite is probably closeto 1.525.
The light-gray color of the sample is probably due to the admixed
darker clay, pure bradleyite being probably white or colorless.
The specific gravity of the sample analyzed, determined with a pycnometer, using toluol, is2.646. That of the clay, determined in the sameway, is 2.I4l.Erom thesevaluesand the percentageof clay in the bradleyite sample, the specificgravity of pure bradleyite was calculated to be
2.734. By applying the Gladstone Dale equation a good check on thespecificgravity was obtained with the figure 2.725.
No value for hardnesscould be obtained.
X-nay ANar,vsrs By GEoRGETuNsr,L
X-ray powder difiraction photographs were made of natural bradleyite mixed with 15 per cent of oil shale with use of copper K-radiation
filtered through nickel foil, and for comparison, diffraction photographs
were made in the same camera, also with use of copper K-radiation filtered through nickel foil, of the oil shale from which the bradleyite had

JOSEPHJ. FAHEY AND GEORGETUNELL

648

been removedby solution,and also of magnesite.The next strongestlineof the oil shale pattern is not present at all on the films of bradleyite
mixed with 15 per cent of oil shale, and the strongest line of the oil shale
pattern if present at all merely adds very slightly to a strong line ofbradleyite with which it is almost coincident. The remaining lines of theoil shale pattern are not visible on the powder photograph of bradleyite.
The lines of the powder difiraction pattern of bradleyite are listed inTable 1. The intensitieswere estimated visuallv on a scaleof ten, whereTasr,B 1. PuNrrn

or rnn DrlnnecuoNSp,rctNcs .qmo RnrerrvB Inrnxsrurs
rne X-nev Powonn Specrnuu or Bna.ntnvnn(Fiitered CuK-radiation)
Intensity

Spacing

8 9394.
3.680
3.319
2 969
2.658
2.566
2.467
2 388

3

1 .s 9 8 4
1.562
1 494
1 443
1. 3 8 51 331
1 288
1.25r
1.224
1.186
1 .1 5 1
1.101
1 068
1 038
1 011
0.987

L1082I2z. Jl.)

I

2 209
2.116
2.025
1. 9 3 5
1 842
1 760
1.704
1. 6 5 83+2

1248I

2I
2rN

(Filtered CuK-radiation)
Intensity

Spacing

10LtxlsI
234342L(broad)oten represents the intensity of the strongest line. Several powder diffraction photographs of bradleyite mixed with 15 per cent oil shale weremade and one of bradleyite and oil shale mixed with sodium chloride.
The spacings of the bradleyite lines were determined by comparison
with the sodium chloride lines on the latter fiIm.
The powder photographs of bradleyite and magnesite were comparedto establish the fact that bradleyite is not composed of a mixture ofmagnesiteand some other compound; there is no line on the powder photograph of bradleyite corresponding to the strongest line of the magnesite pattern; hence, the presenceof any substantial proportion of magnesite in bradleyite is excluded. There is no reason to supposefrom theevidence of the r-ray photographs that bradleyite is a mixture.

649

BRADLEYITE, A NEW MINERAL

Frc. 1. X-ray powder photographs of (A) bradleyite and (B) magnesite
taken with filtered copper K-radiation.

CnBurcar, C olrposrrroN
Part of the one-inch layer of bradleyite was crushed, care being taken
to avoid as much as possible the formation of fines. The crushed material
was then sieved and that portion passing60 mesh and retained on 100
mesh was passedthrough the Frantz isodynamic magnetic separator bywhich means most of the shortite was removed. The final sample (about15 grams) was estima"tedby microscopicexamination to contain lessthan
one per cent of shortite. It was not possible to remove the clay so thesample analyzed consistedof about 85 per cent of bradleyite, 14 per centof clay, and one per cent of shortite.
Bradleyite is very slowly decomposed by cold water, only a few percent of sodium carbonategoing into solution when allowed to stand overnight. Water was determined by loss in both the sample analyzed andin the separated clay, and properly allocated. The bradleyite was dissolved, by treatment for one minute with cold ten per cent hydrochloric
acid solution, leaving a residue of clay. The clay was filtered off, airdried, and weighed.The other constituentswere obtained in the filtrate.
AN,lr,vsrs ol Bnalr,evrro
ClayMso
NapO
PzOu
COz
FerOa
Al203
CaO
SO,CI
SiOz
HzO below 100" C.
HzO above 100' C.
KzO

1+.46
12.9r
31.62
22.03
1 5. 8 0
0.52
o.24
0.36
0.46
(, . .J.)

0.02
0 .3 0None
None
99.07

TOSEPH J. FAHEY AND GEORGE TUNELL

CoupurarroN on Fonuura
The CaO (0.36%) found in the analysis was consideredto have comefrom the shortite present and the NazO and COz equivalents were deducted before computing the formula. In the sample no minerals containing chlorine or sulfate were observed.Hence the fractional percentagesof theseconstituentswere not applied as correctionsin the computations.
Per cent

Molecular ratios

NurO
31.42
0.507:3.04
MgO
12.91
0.323:r.93
PzOs
22.03
0.155:0.93
COz
15.38
0.350:2.10
Formula:3NazO2MgO.2COz.&Osor NaaPOr'MgCO:or Na3MgCO3pOl.
In the absenceof morphologic evidence the proof that bradleyite is acompound and not a mixture rests chiefly on the chemical and &-ray
data. Tunell has shown that there is no magnesite in the sample of bradleyite that was analyzed. The low solubility of bradleyite in water (lessthan 5 per cent in 20 hours) rules out the possibility that either sodium
phosphate or sodium carbonate may be present as separate compounds;
furthermore, the simple atomic ratios indicate the existenceof a definite
compound.