Contributions to 

Geochemistry 

964-68

GEOLOGICAL SURVEY BULLETIN 1214

This volume was published as 

\eparate chapters A-H.
UNITED STATES DEPARTMENT OF THE INTERIOR 

WALTER J. HICKEL, Secretary

GEOLOGICAL SURVEY 

William T. Pecora, Director
CONTENTS

[Letters designate the separately published chapters]

(A) Geochemistry of the platinum metals, by Thomas L. Wright and Michael 

Fleischer.

(B) Ruinate in coastal sands of northwest Florida, by Vernon E. Swanson 

and James G. Palacas.

(C) Beryllium content of volcanic rocks, by Daniel R. Shawe and Stanley 

Bernold.

(D) The determination of sulfate and sulfide sulfur in rocks or minerals, by

by Angelina C. Vlisidis. 

(E) Element distribution in some shelf and eugeosynclinial black shales, by

James D. Vine.

(F) Determination of nitrates in saline minerals, by Laura E. Reichen and 

Joseph J. Fahey.

(G) Element distribution in some Paleozoic black shales and associated rocks,

by James D. Vine. 

(H) Element distribution in some trough and platform types of black shale and

associated rocks, by James D. Vine, Elizabeth B. Turtelot, and John

R. Keith.
Geochemistry of the 

Platinum Metals

By THOMAS L. WRIGHT and MICHAEL FLEISCHER

CONTRIBUTIONS TO GEOCHEMISTRY 

GEOLOGICAL SURVEY BULLETIN 1 2 1 4-A

^ Abundance and ranges of composition 

of the platinum metals in various rocks 

and meteorites are summarized from 

the literature

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

The U.S. Geological Survey Library has catalogued this publication as follows:

Wright, Thomas Llewellyn, 1935-

Geochemistry of the platinum metals, by Thomas L. 

Wright and Michael Fleischer. Washington, U.S. Govt. 

Print. Off., 1965.

iv, 24 p. tables. 24 cm. (U.S. Geological Survey. Bulletin 

1214-A)

Contributions to geochemistry.

Bibliography: p. 20-24.

1. Platinum group. I. Fleischer, Michael, 1908- joint author. 

II. Title. (Series)

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 15 cents (paper cover)
CONTENTS

Page

Abstract-____.___.______________________-_-____--__---__-_-.-_--- Al

General geochemical considerations._________________________________ 2

Mineralogy of the platinum metals___-_____-___-_-___-__--_--_.--_-- 3

Alloys and intermetallic compounds______-___-__--__-_____-__-- 4

 Compounds with oxygen, sulfur, tellurium, arsenic, antimony, bismuth,

and tin_________ ________________________________________ 7

Minerals that contain platinum metals as trace constituents._______ 9

Occurrence and abundance of platinum metals___-______-__-___--___-_ 11

In rocks--_______________-_______-_______-_-___-_-_____--__--_ 11

Uncertainties in the data._____-_____-___________-_____-___- 11

Igneous rocks-_-_-___-_____-_-_---_-___-_-_---_----_.--_-- 12

Sedimentary rocks..________________________________________ 14

Metamorphic rocks. _______________________________________ 14

Average abundances.______________________________________ 15

In the earth's crust__________________________________________ 15

In meteoritic matter__________________._-___________-____.__-_- 16

Cosmic abundance _-___________-___-_-_-_--__-___-___--__--- 19

Suggestions for future study________________________________________ 20

References______________________________________________________ 20

TABLES

Page 

TABLE 1. Atomic properties of the platinum metals__________________ A2

2. Isotopic composition of the platinum metals._______________ 3

3. Glossary of names of alloys and intermetallic compounds of 

fc, the platinum metals.__________________________________ 5

4. Ranges of chemical composition of alloys and intermetallic 

w compounds of the platinum metals--_-_______-____-__-__ 6

5. Glossary of names of compounds of the platinum metals with 

oxygen, sulfur, tellurium, arsenic, antimony, bismuth, and 

tin___.__.______________________________ 7

* 6. Compounds of the platinum metals grouped by anions_-_--_- 8

7. Chemical composition of compounds of the platinum metals __ 8

8. Total platinum metals content reported in sulfides, selenides, 

^, tellurides, and arsenides______________________________ 9

9. Maximum contents of total platinum metals in minerals. _ . _ . 10

10. Average content of platinum, palladium, and rhodium in

sulfide minerals_______________________________________ 11

** 11. Summary of abundance data on platinum metals in rocks.._. 13 

12. Platinum metals in sedimentary rocks.____________________ 14

*" 13. Estimated abundance of platinum metals in the earth's crust. 16

* ni
IV CONTENTS

Page

TABLE 14. Comparison of the relative amounts of platinum metals 

recovered by industrial processes with that computed from 

their natural abundance-_--_____________-_----_-__-_-__ A16

15. Platinum metals in individual meteorites____-___-_-_____-__ 17

16. Distribution of the platinum metals in phases of chondrites_ 18

17. Recent estimates of the average content of platinum metals in

meteorites__________________________________________ 18

18. Recent estimates of cosmic"abundance of the platinum metals. 19
CONTRIBUTIONS TO GEOCHEMISTRY

GEOCHEMISTRY OF THE PLATINUM METALS

By THOMAS L. WEIGHT and MICHAEL FLEISCHER

ABSTRACT

This paper summarizes the literature pertaining to the geochemistry of the 

platinum metals. The platinum metals platinum, iridium, osmium, palladium, 

rhodium, and ruthenium occur as alloys of metals, as intermetallic compounds, 

and as compounds with oxygen, sulfur, tellurium, arsenic, antimony, tin, and 

bismuth. The synonomy and known ranges of composition of platinum-metal 

compounds are summarized in tables. Platinum metals also occur as trace constituents of rock-forming minerals, in amounts as much as 10 ppm, although commonly less than 1 ppm. The form in which platinum metals occur in these 

minerals is imperfectly known.

Platinum metals are unevenly distributed throughout rock masses, probably 

in the form of pure metals or alloys. Data for content of platinum metals in 

rocks are of uncertain reliability owing to inherent sampling difficulties and to 

errors in the analytical procedures. The following abundances are estimated to 

within one order of magnitude: Ultramafic rocks (0.05 ppm); mafic igneous 

rocks (0.02 ppm); silicic and intermediate igneous rocks (0.005 ppm). In general, 

data are insufficient to give estimates for metamorphic and common sedimentary 

rocks. Some uncommon sediments for example, copper-bearing shale, coal 

ash have platinum-metal contents as high as 1 ppm.

Recent estimates of crustal abundances of the platinum metals are as follows 

(all values in ppm): Palladium, 0.01-0.02; platinum, 0.005; iridium, osmium, 

rhodium, and ruthenium, all less than 0.001. Data for industrial recovery of 

platinum metals indicate a much greater recovery of platinum than of palladium, 

which suggests that the crustal abundance figures for platinum and palladium 

should be reversed.

Meteorites contain more platinum metals than crustal rocks; siderites contain, 

on the average, 30 ppm total platinum metals compared with 4 ppm in chondrites. 

In individual meteorites, platinum and iridium are largely concentrated in the 

iron phase, whereas osmium, iridium, ruthenium, and rhodium are also present in 

significant amounts in the troilite (sulfide) phase. The following average contents 

of the platinum metals in meteorites have been calculated from data in the literature (all values in ppm): Platinum, 2.8; osmium, 1.7; ruthenium, 1.6; palladium, 

1.4; iridium, 0.7; rhodium, 0.6.

The cosmic abundances of the platinum metals, as summarized from the recent 

literature, are as follows (atoms per 10° atoms silicon): platinum, 1.3-1.6; ruthenium, 1.5-0.9; osmium, 1.0-0.6; iridium, 0.8-0.5; palladium, 0.7-0.6; rhodium, 0.2.

Al
A2 CONTRIBUTIONS TO GEOCHEMISTRY

GENERAL, GEO CHEMICAL CONSIDERATIONS

The platinum metals comprise the six heavier metals of group VIII 

of the periodic table of the elements. They are conventionally 

separated into two subgroups: the light platinum metals (of lower 

atomic weights) ruthenium (Ru), rhodium (Rh), and palladium (Pd) 

and the heavy platinum metals osmium (Os), iridium (Ir), and 

platinum (Ft). Atomic weights and metallic and covalent radii of 

the platinum metals are given in table 1 and isotopic abundances are 

summarized in table 2. Solid solution among the platinum metals is 

extensive, because of the similarity in their metallic radii. These 

metals also combine with or can be replaced in part by significant 

amounts of Fe (radius 1.27 A.), Ni (radius 1.24 A.), and Cu (radius 

1.28 A.).

The platinum metals are strongly siderophilic and chalcophilic 

that is, they occur predominantly as pure metals and alloys and to a 

much lesser extent combined with sulfur, tellurium, and arsenic. 

They occur in rock-forming silicates in small to negligible amounts. 

For the most part the platinum metals are concentrated in the early 

stages of magmatic differentiation and consequently are most abundant in magmatic mafic and ultramafic bodies and associated ore 

deposits. Under certain conditions, as yet imperfectly known, the 

platinum metals are carried through the differentiation process because 

of their lack of affinity for the silicate minerals and are then concentrated hi the products of late hydrothermal solutions.

Economically valuable deposits of the platinum metals are restricted almost entirely to areas within or near masses of mafic and 

ultramafic rocks. The platinum metals in the primary deposits are 

closely associated with sulfides especially of the chalcopyritepyrrhotite-pentlandite assemblage or with chromite, but much of 

the world's supply has come from placer deposits derived from ultramafic rocks in which traces of platinum metals were originally 

disseminated.

Previous reviews of the geochemistry of the platinum metals 

may be foundjm Goldschmidt (1954, p. 677-695), Rankama and

TABLE 1. Atomic properties of the platinum metals

Atomic No _____ 

A+nmip wpiffllti 1

Metallic radius, A_ 

Octahedral covalent

Ru

44

101.07

1.34

1.33

Eh

45

102.05

1.34

1.32

Pd

46

106.4

1.37

1.31

Os

76

190.2

1.35

1.33

Ir

77

192.2

1.35

1.32

pt

78

1QC AQ

1.38

1.31

11961 scale based on carbon-12.
GEOCHEMISTRY OF THE PLATINUM METALS A3

TABLE 2. Isotopic composition, in percent, of the platinum metals

1. Ruthenium

Reference

Seaborg and Perlman 

(1948) 

Friedman and Irsa

MQ&1A

White, Collins, and

Feitknecht, Herr, and

Do.. 

Abundance (percent) for indicated mass No. 

94

<0.01

95

<0.01

95

fi 68

5 fin

5.57 

fi, 52

5 52

97

<0.01

98

2 22

1 91

1.86

1 85

1,84

99

12.81

12.70

12.7 

12.72

12.74

100

12.70

12.69

12.6 

12.53

12.61

101

16.98

17.01

17.1 

17.09

17.07

102

31.34

31.52

31.5 

31.54

31.60

103

<0. 0001

104

18.67

18.67

18.5 

18.74

18.62

105

<0. 0007

2. Rhodium

[Rbio3=100.0 (Reference: Seaborg and Perlman, 1948)]

3. Palladium

Reference 102

0.8

.96

 104

9.3

10.97

105

22.6

22.23

106

27.2

27.33

108

26.8

26.71

110

13.5

U B1

4. Osmium

Reference

Seaborg and Perlman (1948)

184

0.018

186

1.59

187

1.64

188

13.3

189

16.1

190

26.4

192

41.0

5. Iridium

[Irm=38.5; Iru3=61.5 (Reference: Seaborg and Perlman, 1948)]

6. Platinum

Reference

Seaborg and Perlman (1948) ... 

Leland (1949) -. .

Duckworth and 

others (1952) _ 

Lopez de Azcona 

(1955). 

White, Collins, 

and Rourke 

(1956). 

188

<0.002 

<.0013

189

---. -

<0.002 

<. 0005

190

6.~6l2~

.06 

.0127

191

<0.004 

<.0005

192

0.78

.78 

.78

193

--.---.

<0.009 

<.001

194

32.8

32.8 

32.9

195 

33.7

33.7 

33.8

196

25.4

25.4 

25.2

197

_ ....

<0. 010 

<.001

198

7.23

7.23 

7.19

199

<0.008 

<.001

200

. __ ..

<0.007 

<.001

Sahama (1950, p. 688-694), Zvyagintsev (1946), Zvyagintsev (I960), 

Quiring (1962), and Gmelin (1938).

MINERALOGY OF THE PLATINUM METALS

This section summarizes the chemical composition of the minerals 

in which the platinum minerals occur. The minerals are divided 

into three groups: Alloys of metals, and intermetallic compounds; 

compounds of platinum metals with oxygen, sulfur, tellurium, arsenic, 

antimony, bismuth, and tin; and minerals that contain the platinum
A4 CONTRIBUTIONS TO GEOCHEMISTRY

metals as trace constituents. It is possible that some of the compounds placed in the second group, especially those with bismuth and 

tin, should properly be classed as intermetallic compounds, but more 

data on the crystal structures of the compounds are needed for certain 

classification.

ALLOYS AND INTERMETALLIC COMPOUNDS

The alloys and intermetallic compounds of the platinum-group 

metals are listed alphabetically in table 3 and the ranges of chemical 

composition reported for them are given in table 4. Synonymy is 

indicated in table 3; names that are italicized are considered to rank 

as species.

The nomenclature of the alloys of the platinum metals has been 

confused and has not been consistent, even in the major reference 

books on mineralogy. This is especially true of the indium-osmium 

alloys, which form two distinct series of alloys, cubic and hexagonal. 

In much of the literature, and particularly in commercial work, the 

two series have not been separated, and it is commonly impossible to 

be sure whether material referred to as iridosmine or osmiridium was 

actually the cubic phase, the hexagonal phase, or mixtures of the two. 

The nomenclature used in table 3 is that recommended by Hey (1963).

The cubic alloys include species with platinum, iridium, and palladium dominant; the natural alloys in which platinum is dominant 

are by far the most abundant. Platinum-iridium and platinumpalladium are reported to form complete series of cubic solid solutions 

at high temperatures, but the solubility at low temperatures may be 

limited (Hansen and Anderko, 1958, p. 871, 1121). Platinum also 

forms complete series of cubic solid solutions at high temperatures 

with iron, nickel, and copper (Hansen and Anderko, 1958, p. 616, 

698, 1031), but complex exsolution and reaction phenomena occur on 

cooling, and the limits of solubility of these elements in platinum at 

low temperatures have not yet been determined accurately.

A cubic phase, corresponding to osmiridium of table 3, is stable in 

the system mdium-osmium in the composition range Ir 100-68, Os 

0-32 percent. A hexagonal phase, corresponding to the series iridosmine-osmium of table 3, is stable in the system indium-osmium in the 

composition range Ir 68-0, Os 32-100 percent. It may be expected 

that the position of the boundary between cubic and hexagonal phases 

will be shifted by the presence of other metals; thus the presence of 

ruthenium, which crystallizes in the hexagonal system, would probably 

favor the formation of the hexagonal phase. Data are not yet 

available on the ternary systems.

The hexagonal iridosmine series appears to be much more abundant 

in natural occurrences than the cubic osmiridium. Recent analyses
GEOCHEMISTRY OF THE PLATINUM METALS A5

TABLE 3. Glossary of names of alloys and intermetallic compounds of the platinum 

, metals

[Names in italic are considered to rank as species] 

Mineral Description

Allopalladium. ___________________________ Hexagonal. Pd, with some Pt, Ru,

and Cu, and traces of Ir, Rh, 

Ag, Hg.

Aurosmirid_._ ___________________________ Aurian osmiridium. Cubic. Au

19.3 percent.

Avaite ______________-__-_______--___---_ Synonym of platiniridium.

Cuproplatinum._ _ ________________________ Cuprian platinum.

Eugenesite _ ____________________________ Synonym of allopalladium.

Ferroplatinum __ ________________________ Ferrian platinum.

Gold.. _______--___________.___-__-_-_-_- Reported to contain Pd (see

porpezite), Rh (see rhodite), Ir, 

Pt.

Iridium_-_____-______-_-___--____-__-__- Pure iridium has not yet been

reported. See platiniridium and 

osmiridium.

Iridosmine-osmium series. ________---_--___ Hexagonal. A single series,

divided arbitrarily for convenience into iridosmine, with 

Ir 68-20, Os 32-80 percent, and 

osmium, with Ir 20-0, Os 80- 

100. Iridosmine is divided by 

some authors into the varieties 

nevyanskite with Ir>0s, Ir 

68-50 percent, and sysertskite 

with Os>Ir, Ir 20-50 percent.

Iridosmium_ _____________________________ Synonym of iridosmine.

Nevyanskite. See Iridosmine.

Nickel-platinum. __ _______________________ Nickelian platinum.

Norilskite (Pt, Fe, Ni, Cu) _ _ _ ___ _ ___ A mixture (?) .

Osmiridium--..........-....--....-.----. Cubic. (Ir, Os) with Os up to 32

percent. The name is also used, 

especially commercially, to include the hexagonal alloys 

(iridosmine) .

Osmite____-___--____--_-_--_-__________- Synonym of iridosmine.

Osmium. See iridosmine-osmiuni series.

Palladium. ______________________________ Cubic. Pd, with some Pt, Rh, Ir,

Ru, Os, Pb.

Palladium-amalgam _ ____________________ Synonym of potarite.

Palladiplatinum__________________________ Cubic. Approximately equal

» amounts of Pd and Pt.

Platiniridium...-..-.-...-.-.-----.-.--.- Cubic. (Ir, Pt).

Platinum. _______________________________ Cubic. Pt, with Ir, Pd, Rh, Os,

Au(?), Cu, Fe, Ni. See also 

norilskite, Palladiplatinum. 

w Platinum-nevyanskite_____ ________________ Platinian osmiridium or Iridosmine.

Polyxene. _______________________________ Synonym of platinum.

Porpezite..-___-_______.________. _________ Palladian gold (up to 10 percent

* Pd).

Potor^e________. ________________________ Pd3Hg2 (?) or PdHg(?). Cubic(?).

, Rhodite_____--____-___--__-__________-__ Rhodian gold (up to 43 percent

Rhodium-nevyanskite. ____________________ Rhodian osmiridium or iridosmine. §;{l±ss__s^ if (up to

Ruthenium-sysertskite-____-_________-___J 2L1 Percent Ru>-

Selenpalladium. _______ __ _______________ Synonym of allopalladium (erroneously thought to contain Se). 

Siserskite, sisserskite, sysertskite. See Iridosmine. 

Unnamed Mineral A__ _______ ______ Pd4Pb. Borovskii and others (1959) .

746-814 64 2
TABLE 4. Ranges of chemical composition of alloys and intermetallic compounds of

the platinum metals

 [In weight percent]

Element

Pt

IT........

Os

Pd ....

Rh .__.

Ru. 

Au.......

Fe...... .

Cu.......

Ni... .

Pd 

Sn...... .

Ag.......

Aurosmirid'

51.7

25.5

3.5

19.3

Gold

no. 5

230.4

 a 11.6

a 43?

- 2.6

2.9

Iridosmine-osTniiim

series

0. 2-13. 6

64. 5-3. 7

22. 9-98

0-.6

0-7.7

0-18.3 0-.9

0-2.6 O-.l

Norilskite»

35.5

3.6

25.3

9.3

25.6

Osmiridium

0-11.3

51. 7-72. 5

31. 2-10

0-.6

0-11. 3

0-4

0-2.3

Pallidi- platinumi

48.9

51.1

Palladium

M.6

2.2

2.7

86-100

a 3.0

2.2

28.1

Platiniridumi

19.6

76.9

9.9

1-8

Platinum

55.4-87.2. _ .

1.0-10.4, 

227.8. 

0-0.5 ..

Usually 0-2,

237. 

0.4-6.9 ...

23.6..... ....

2.6-28.0. .

0-13 

0-4. .

0-8 .

Unnamed 

mineral A>

«70

«30

«1

i One analysis.

8 Maximum content reported.

by Levy and Picot (1961) on material checked by X-ray study show 

that the series covers nearly the entire composition range found in the 

u-idium-osmium system. The hexagonal minerals allopalladium and 

potarite are very rare.

The limits of composition of the natural alloys are poorly known, 

but the available data are summarized in table 4, which is based on 

analyses of minerals. Analyses of commercial concentrates of undetermined mineralogy have not been included. The compositional 

ranges indicated for the minerals must be considered to be uncertain, 

partly because of the formidable difficulties of analysis of the platinum 

metals, but mainly because of doubt as to the homogeneity of the 

material analyzed. The alloys of the platinum metals, as well illustrated by Ramdohr (1960, p. 322, 335), Borovskii and others (1959), 

Genkin (1959), and Genkin and others (1962, 1963), commonly occur 

as complex intergrowths of minute grains. It is therefore likely that 

many of the available analyses were made on concentrates that may 

not have been single phases. Much of, and possibly all, the gold 

reported in the analyses was probably present as native gold. Some 

of the copper, iron, and nickel reported was probably present as chalcopyrite, bornite, pentlandite, native copper, and other admixtures. 

Much work is needed, especially analyses of mineral grains proved to 

be homogeneous by optical and X-ray study, to improve our knowledge 

of the compositional limits of these alloys. Especially promising is 

the application of electron-probe analysis, which makes it possible to 

determine the composition of grains as small as 10 microns in diameter.
GEOCHEMISTRY OF THE PLATINUM METALS A7

The use of this method in the past few years has added to our 

knowledge of the series iridosmine-osmium (Levy and Picot, 1961) and 

has resulted in the discovery of many new minerals listed in tables 3 

and 6 (Borovskii and others, 1959; Genkin, 1959; Genkin and others, 

1962, 1963; and Stumpfl, 1961).

COMPOUNDS WITH OXYGEN, SULFUR, TELLURIUM, ARSENIC, 

ANTIMONY, BISMUTH AND TIN

The compounds of the platinum metals are listed alphabetically 

hi table 5 and are grouped by anions in table 6. Names that are 

italicized in table 5 are considered to rank as species. The ranges 

of chemical compositions are given in table 7. It will be noted (table 

5) that many of these minerals have been found recently. The 

minerals of this group are all rare and very few analyses have been 

made only one for many of them so that relatively little is known 

of the possible ranges in composition.

TABLE 5. Glossary of names of compounds of the platinum metals with oxygen, 

sulfur, tellurium, arsenic, antimony, bismuth, and tin

[Names in italic are considered to rank as species]

Mineral

Kotulskite.. ...... .

Niggliite-.... .........

Vysotskite .......... ..

Unnamed new minerals: 

B_ 

0.. ... ...... ..

D ... ... .... ...

E. ...............

F.. ........... ...

G.. ... _.

H ... .... ...

I.... .............

J ..............

K .............

^,.. ..............

Composition

PdsAs ~ .....

(Pt, Pd, Nt)8_. 

(Pt, Pd)S 

PdBij-. . ......

PtSbj ....

Pd(Te, Bi) 1 2 

(Ru, Os)S» - 

PdBij ..........

(Pd, Pt)BiTe. .

(Pt, Pd) (Te, Bi)2.

PtSn(?).. .........

PdO(?) ... ... ...

PtAsj 

(Pd, Pt) 3 Snj......

PtsSni(?) ..........

PdsSb .........

(Pd, Ni, Pt)S 

(Pt, Ir)As2 ._ 

Pt(Ir, Os)As4.-._

PfTVT A«!n

PtSb . ..........

Pt(Sb, Bi).. 

Pd(Sb, Bi). ....

PtPdSn... .....

System

Cubic 

- do......

.... .do..-.-

Cubic 

Tetragonal..

 ..do......

 do......

Reference

Stumpfl (1961) ..._ -

(1963).

(1963).

Genkin and Zvyagintsev, (1962).

Stumpfl (1961)-. 

 .do......... ....

(1959). 

Stumpfl (1961)--.. 

__ do.. . .__ 

 .do........ .....

Hawley (1962, p. 95-

96). 

Stumpfl (1961).... .

 .do.... ... 

.... .do.. .. .....

(1959).

Remarks

From Sudbury, Ontario.

U.S.S.R.

Possibly PtTe(?).

No analysis.

Sperrylite(?).

M = 0s(?).

Bismuthian variety of

E(?).

From Sudbury. Not

froodite or michenerite.
CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 6. Compounds of the platinum metals grouped by anions 

[The metal listed is the dominant one]

Oxides _____ Pd (palladinite) (?) 

Sulfides_______ Pt (braggite, cooperite)

Pd (vysotskite)

Ru (laurite) 

Tellurides_____ Pt (moncheite, nigPd (kotulskite) 

Arsenides _____ Pt (sperrylite, unnamed B, C, D) 

Pd (arsenopalladinite)

Antimonides_ Pt (geversite, unnamed E, F) 

Pd (stibopalladinite, 

unnamed G, I, J)

Bismuthides_ Pt (moncheite, unnamed F)

Pd (froodite, kotulskite, michenerite, 

unnamed G, H)

Stannides_____ Pt (niggliite(?), stannoplatinite, unnamed K, L)

TABLE 7. Chemical composition of compounds of the platinum metals 

[In weight percent]

Element

pt

Ir.........

Os ... 

Pd 

Rh _ ....

Ru.......

An

Fe 

Cu.. ...

Ni 

Pd .....

S. ........

To

As 

Sb ....

Bi.. ......

Sn........

Element

Pt.. 

Ir....... ..

Os .... .

Pd 

Rh... .

Ru... .

Au ...

Fe 

Cu 

Ni 

Pd .... .

S... 

Te-. 

As 

Sb... 

Bi.. .

Sn 

Braggite

59 

Present

18-20. 9 

Present 

Present

2.8-4.7

16.8-19.0

Cooperite

80. 3-82. 5 

Present

0-4.3

0- .1

14.3-17.5

Stibiopalladinite

70.4-73

25-28

Geversite i

45

51.5

Vysotskite

4.1-5.5

57.1-61.9

14.2-16.6

Kotulskite »

31.1

""~44"6"

24.9

Laurite

33.0

65-67

31.8-33

Michene 

rite

8. 4- 9. 3

11.7-16.9

28.~J£37T6~

42.3-45.0

Moncheite

22. 3-30. 8

4.6- 9-2

33.~5^55T

9.2-31.7

Sperrylite

52.6-63

Trace 

0- 1.7

0- .7 

0- .7

59.9-41.9

0- .5

(M

Stannopalladinite

15-20

40-45

0.3-2.3 

5-12 

0.1- .7

28-33

Unnamed mineral [based on one analysis each]

B

47.0 

5.0

......

46.8

C

22.0 

Major 

Major

32.5

D

«36

......

«3

»28

E

50.5

......

34.7

F

50.5

......

26.4

15.3

G

43.6

25.2

32.2

I

53.5

16 0

31 S

J

6.0

62.0

5.0

30.0

K

51.7

......

16.8

22.0

L

«50 

«2.5

28

«30

1 One analysis.

* Maximum content reported.
GEOCHEMISTRY OF THE PLATINUM METALS A9

MINERALS THAT CONTAIN PLATINUM METALS AS TRACE

CONSTITUENTS

The platinum metals have been reported to occur as trace constituents in members of all mineral groups except the carbonates and 

nitrates, and especially in sulfides, selenides, tellurides, and arsenides. 

The microscopic features of the minerals analyzed are not described 

in most of the papers; it is probable that at least part of the platinum 

metals reported were present as discrete minerals rather than as solid 

solutions. Additional uncertainty is caused by the difficulties of 

analysis; for example, it is known that osmium and rhodium are likely 

to be lost in part during cupellation and are therefore likely to be low 

in analyses made by first collecting the platinum metals in assay beads. 

Analyses of more than 200 minerals and rocks for all 6 platinum metals 

are given by Noddack and Noddack (1931); mentioned here are those 

minerals that contained more than 1 ppm total platinum metals.

Such data as are available on sulfides and arsenides are given in 

table 8. It is evident that precise analyses on material of known 

homogeneity are badly needed. Many additional determinations are 

given by Hawley and Rimsaite (1953) from Canadian ore deposits 

and by Schneiderhohn and Moritz (1931) for sulfides of the Merensky 

Reef of the Bush veld complex, South Africa; the maximum contents

TABLE 8. Total platinum-metals content, in parts per million, reported in sulfides, 

selenides, tellurides, and arsenides

[See also tables 9 and 10]

Mineral and locality

Hessite, Altai, U.S.S.R _________

Argentite, Freiberg, Germany________

Berzelianite, Skrikerum, Sweden______

Galena ____________________________

Clausthalite, Tilk erode, Germany _ __

Altaite, Altai, U.S.S.R.... _ ._.....

Sphalerite- ___ ________ __ _______

Chalcopyrite. ______________________

Pyrrhotite, Evje, Norway __ _______

Pyrrhotite, Froyssa, Norway... ______

Pyrrhotite, Sulitelma, Norway. ______

Pentlandite, Espedalen, Norway______

Molybdenite- _--_-_--_-___-________

Cobaltite, Skutterud, Norway________

Gersdorffite, Loos, Sweden. __ ________

Niccolite, Mansfeld, Germany________

"Arsensilber," Andreasberg, Germany. 

Domeykite, Paracatas, Mexico. ______

Total platinum 

metals

137

16

15.6

1,2,5

135

44

1.5,7

1

7.8

5.3

1

7.2

1.7

2

8

4

24 

5

Reference

Noddack and Noddack

(1931). 

Do.

Do.

Gmelin (1938).

Noddack and Noddack

(1931). 

Do.

Gmelin (1938).

Do.

Noddack and Noddack

(1931). 

Do.

Do.

Do.

Gmelin (1938).

Noddack and Noddack

(1931). 

Do.

Do.

Do. 

Do.
A10 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 9. Maximum contents of total platinum metals in minerals

fin ppm]

Location

Canadian ore deposits: 

Nickeliferous sulflde ores.

Nonnickeliferous sulflde

Creighton Mine, Sudbury,

complex S. Africa.

Pyrite

0.7 

.012

Pyrrhotite

9.8 

.056

2.59

50

Chalcopyrite

35.8 

1.12

».77

Pentlandite

4.8

<6.6

50

Mixed 

arsenides

1247 

.11

Nickel 

pyrite

50

50

Reference

Hawley and Rimsaite 

(1953).

Do.

(1963).

Moritz (1931).

1 Nearly all palladium, with trace of platinum, 

a Pt, 0.50; Pd, 0.09. 

»Pt, 0.76; Pd, 0.011. 

«Pt, 6.3; Pd, 0.3.

given are listed in table 9. For comparison, recent data by Morris, 

Hill, and Smith (1963) are given. These were made by neutronactivation analysis; all others are spectrographic analyses. The data 

for the Canadian deposits show much higher content of total platinum 

metals in nickeliferous ores than in nonnickeliferous ores.

Averages of analyses for platinum, palladium, and rhodium for 

ores from Sudbury, Ontario, and from NoriPsk, U.S.S.R., are given in 

table 10. The ratios of the three elements in the two deposits are 

very different, but both sets of data show much higher relative contents 

of rhodium in pyrrhotite than in chalcopyrite.

Oxide minerals that have been reported to contain more than 1 

ppm of total platinum metals are pyrolusite (14 ppm), psilomelane 

(4.9 ppm), cassiterite (1 ppm), columbite (3.45, 3 and 1.9 ppm), and 

chromite (2.35, 4.4 ppm, Noddack and Noddack, 1931). Up to 20 

ppm total platinum metals was found in chromites from the South 

African platinum deposits (Schneiderhohn and Moritz, 1931); chromite from eclogite pegmatite contained 0.24 to 1.15 ppm (Lunde and 

Johnson, 1928).

Traces of platinum metals were reported in sylvite (0.0007-0.0034 

ppm) and in carnallite (0.0001-0.003 ppm) from German salt deposits 

(Goubeau and Birkenbach, 1938).

Contents of more than 1 ppm of total platinum metals have been 

reported for the following silicates: zircon, variety alvite, 10.4 ppm; 

gadolinite, 2.9, 8.4 ppm; and thortveitite, 8.3 ppm (Noddack and 

Noddack, 1931). These, as well as columbite of the oxide minerals, 

are formed in late stages of granitic pegmatites, which suggests that 

smaU amounts of the platinum metals remain in solution throughout 

the cycle of igneous differentiation, and precipitate in the final stages.
GEOCHEMISTRY OF THE PLATINUM METALS All 

TABLE 10. Average content of platinum, palladium, and rhodium in sulfide minerals

Mineral

Number of 

samples

Total 

platinum 

metals (ppm)

Pt Pd Eh

Percent of total platinum 

metals

Sudbury, Ontario'

Pyrite _________,.__-__-__--_--_- 4

17

4

8

2.60

1.50

6.70

7.74

54.9

46.0

31.0

19.0

41.6

42.4

60.8

80.2

3.5

11.6

8.2

.8

Noril'sk, U.S.S.R."

Pyrrhotite (veins) _______________

Pyrrhotite (incrustations) ________

Chalcopyrite (veins) _____________

Chalcopyrite (incrustations) ______

19

20.6

4. 5

5. 14

10.6

12.6

17.0

9.7

52.5

72.7

83.0

89.5

36.9

14.5

.8

1 Summarized from Hawley (1662), tables 16-17, p. 124-125.

2 Summarized from Qinzburg and Rogover (1961).

Rock-forming silicates reported to contain small amounts of 

platinum metals include olivine (0.19 ppm), pyroxene (0.03 ppm), 

serpentine (0.05,0.18 ppm), hornblende (0.03 ppm), garnet (0.01 ppm), 

and orthoclase (0.03 ppm, Noddack and Noddack, 1931). Eclogite 

minerals reported to contain platinum metals are pyroxene (0.01, 

0.07 ppm), and garnet (0.02, 0.02 ppm, Lunde and Johnson, 1928). 

As no microscope observations are given, the form of occurrence in 

these minerals is not known.

OCCURRENCE AND ABUNDANCE OF PLATINUM METALS

IN ROCKS 

UNCERTAINTIES IN THE DATA

Published analytical data for platinum metals in rocks are subject 

to errors derived from inherent sampling difficulties and from analytical uncertainties. Platinum metals are distributed nonuniformly 

throughout rock masses because of their tendency to crystallize as 

pure metals and alloys instead of as substituting ions in the lattices 

of rock-forming silicates. Hence, it is difficult to obtain representative samples of rock for analysis. Lunde and Johnson (1928, p. 190) 

analyzed seven samples of a single body of peridotite and found 

platinum-metal contents ranging from 0.075 ppm to 0.74 ppm and 

differing by a factor of nearly 10. Hahn-Weinheimer and Rost 

(1961, p. 175) found a similar scatter in analyses of five samples of a 

single body of serpentine; palladium ranged from 0.06 to 0.83 ppm, 

platinum from 0 to 0.22 ppm, and the sum of platinum and palladium
A12 CONTRIBUTIONS TO GEOCHEMISTRY

ranged from 0.11 to 1.05 ppm making a total difference of nearly 

an order of magnitude. Hagen, 1 in 1954, reported analyses of composite samples of Deccan plateau basalts which differed for palladium 

by a factor of two and for platinum by a factor of four.

Analytical uncertainties hi the method of fire assay are discussed 

by Hagen, including a lengthy treatment of the corrections for losses 

during analysis. Corrections used by Hagen were large (as much as 

a factor of two) and were based on composite samples, thereby reducing the precision of data for individual samples. Vincent and Smales 

(1956) analyzed by neutron activation the same sample of Mooihoek 

dunite that Hagen analyzed spectrographically. Vincent and Smales' 

value of 0.125 ppm Pd differs from Hagen's value of 0.065 ppm Pd 

by a factor of two. This difference may reflect both sample inhomogeneity and analytical errors.

Because of the uncertainties involved, the platinum metal contents 

cited in table 11 and discussed in the following section should not be 

accepted as having an accuracy of greater than one order of magnitude.

IGNEOUS BOCKS

Data on the content of platinum metals in igneous rocks are scanty 

and scattered through a wide literature. Most of the data pertain to 

ultramafic rocks, the silicic and intermediate rocks having been 

almost completely ignored. Hagen 1 reports spectrographic analyses, 

after concentration by fire assay, of Pt and Pd in 77 igneous rocks 

samples, 35 of which are from the Bushveld complex (Transvaal). 

Because of the large number of samples and the recent date of the 

study, Hagen's data form the basis for much of the discussion in this 

section. His results are summarized in table 11.

Economically valuable deposits of platinum metals have been 

universally found associated with mafic and ultramafic rocks. As 

a result the data on abundance are heavily weighted in favor of 

these rocks to the virtual exclusion of more silicic igneous rocks 

and sediment and metamorphic rocks. The abundance of platinum 

metals in a single ultramafic rock unit or ultramafic rocks within a 

single petrologic province is given by Hagen 2 in 1954, Lunde 

(1927), Lunde and Johnson (1928), Schneiderhohn and Moritz (1931), 

Cotelo Neiva (1949), Hahn-Weinheimer (1959), and Hahn-Weinheimer 

and Host (1961). Additional values for miscellaneous ultramafic 

rock units are given by Leutwein (1939), Du Rietz (1956), Vincent 

and Smales (1956), and Hagen.3 The maximum contents of platinumgroup metals reported for ultramafic rocks other than those cited in

1 Hagen, J. C., 1954, Some aspects of the geochemistry of platinum, palladium, and gold in igneous rocks 

with special reference to the Bushveld complex, Transvaal: Massachusetts Inst. Technology, [Cambridge], 

unpub. Ph. D. thesis.

3 Hagen, op. cit.

»Hagen, op. cit.
GEOCHEMISTRY OF THE PLATINUM METALS Aid 

TABLE 11. Summary of abundance data (ppm) on platinum metals in rocks l

Rock type

Bushveld silicic rocks _ 

U.S.A. silicic rocks_____

Westerly, R.I., granite

(G-l). 

Basalts. ______________

Diabases __ _________

Centerville diabase

(W-l). 

Bushveld gabbros______

Other gabbros_ ________

Skaergaard (chilled 

marginal gabbro).

Sudbury norites, ______

Bushveld peridotites... 

Other peridotites. _____

Bushveld pyroxenites _

Onverwacht (Bushveld) dunites: 

Olivine (outer)

Hortonolite

(inner). 

Mooihoek (Bushveld) 

dunites: 

Olivine (outer) ____

Hortonolite 

(inner) . 

Bushveld anorthosites__ 

Essex anorthosite. _____

Igneous rocks 3 -_______

Number of 

samples

4 

2

15

5

4

4

2 

7

2

2 

3

7 

2

2

2 

1

27

Pt

0.003 

.003

.026

.037

.021

.019

.018 

.038

.011

.017 

.018

.048 

.009

.018

3.17

.066

12.3, .26

.075 

.004

.011

.005

Pd

0.005 

.003

2 .01

.041

.016

f .20

\ .017 

.031

.020

.018 

.015

.006

.012 

.011

.059 

.003

.004

.013

.065

.26, .023

.032 

.003

.017

.02

Reference

Hagen, 1954. 

Do.

Ahrens and Fleischer,

1960. 

Fleischer and Stevens, 

1962. 

Hagen, 1954.

Do.

Ahrens and Fleischer,

1960. 

Fleischer and Stevens, 

1962. 

Hagen, 1954.

Do.

Vincent and S males, 

1956. 

Hagen, 1954.

Do.

Do. 

Do.

Do. 

Do.

} Do.

\ Do.

Do. 

Do.

Do.

Vinogradov, 1956.

1 Table modified and enlarged from Hagen (1954) table 2-24, p. 103. 

a Also contains Ir=0.0063 ppm.

8 2 parts acidic to 1 part basic. Qualitative estimates of abundance for the other platinum-group metals 

as follows: Ru=0.0001; Rh = .001; Os=.0001; Ir=.001.

table 11 are as follows: dunite (30 ppm); peridotite (0.74 ppm); 

pyroxenite (0.6 ppm); serpentinite (1.05 ppm).

The contents of platinum metals in igneous rocks other than ultramafic are given by Hagen 4 and Noddack and Noddack (1931). 

Hagen's data for palladium and platinum are summarized in table 11. 

Data on three different basalts presented by the Noddacks are as 

follows: 0.21 ppm, 0.03 ppm, and 0.05 ppm total platinum metals. 

These values are consistent with Hagen's average for basalt (Pt+Pd 

=0.067 ppm) and the Pd content of W-l (0.02 ppm) reported in 

table 11. The Noddacks also report values of 0.02, 0.01, and 0.05 

ppm in 3 different granites. The Pd content of G-l is reported as

4 Hagen, op. cit.
A14 CONTRIBUTIONS TO GEOCHEMISTRY

less than 0.01 ppm (table 11). No quantitative determinations of 

platinum metals in intermediate rocks exist.

SEDIMENTARY ROCKS

Determinations of platinum metals in sedimentary rocks are few 

and are mostly from unusual or uncommon rock types; none is from 

sandstone, limestone, or ordinary shale. During the weathering 

cycle the platinum metals, by virtue of their high specific gravity 

and low solubility, are largely concentrated as placer deposits, and 

therefore their abundance in ordinary sedimentary rocks is quite low. 

The abundances of platinum metals in sedimentary deposits are 

summarized in table 12. The highest contents of Pt and Pd are 

found in the Mansfeld copper-bearing shale of Germany (0.02-0.05 

ppm), where these metals may be associated with sulfides, and in 

coal ash (up to 0.5 ppm).

TABLE 12. Platinum metals in sedimentary rocks 

[D, detected, no value given]

Rock type

Copper-bearing shale (Mansfeld). 

Do . ....

Black sbale ................

Bleached shale ...............

Sand. ___ .... _____ ...

Loam... _________

Coal (clarite) (in ash). .......

Coal (Steinkohle) (in ash)....

Fine potter's clay. ...........

Hematitic flint clay ..........

Recent montmorillonite clay. 

Pink kaolin......

German K-salt deposits, 

saline clays. 

Rock surrounding the saline 

layers.

Abundance (ppm) for indicated element

Pt

0.0001

.05 

.05

.05 

.01 

.05

.05 

.01 

.007

.04 

.01 

.02

.2

.1-.5

.2-. 5

.2-. 5

Ir

0. 0001 

.004

<-5(?)

Os

0.003

.05-. 5

.2-. 5

<.2 

D 

D

D

Pd

0. 0001

.02 

<.05 

 COS 

<.05 

<.05 

<.05 

<.05

.02

D

Rh

0.0002 

<.01 

.02 

.01 

.02 

<.01 

<.01

D

Ru

0.003 

.06 

.08 

.04 

.04 

.005 

.02

Total platinum metals

0. 0009-0. 092 

0. 0006- . 174

Reference

Cissarz and Moritz, 

1933. 

Noddack, 1936. 

Tischendorf, 1959.

Do.

Quiring, 1962.

Do.

Goldschmidt and 

Peters, 1933. 

Do. 

Goldschmidt and 

others, 1948. 

Do. 

Ahrens, 1945. 

Do. 

limori and Yoshimura, 1929. 

Smales and Wiseman 

1955.

Goubeau and Birkenbach, 1938. 

Do.

METAMORPHIC ROCKS

Determinations of platinum-metal content of metamorphic rocks 

are scarce, and where such measurements are reported they are 

invariably given for rocks in a generally ultramafic terrain either
lOJ-O-iJ. VJ.' JLJ=Lu _. .LU-J..LU Ul i. lUiii

metamorphosed ultramafics or contact rocks adjacent to an ultramafic 

massif. The platinum-metal content of a pyroxene-calcite rock 

(sagvandite) listed by Lunde and Johnson (1928) is as follows:

Content 

Sample 1 (ppm)

Fresh sagvandite__-__---___-___-_-------------_-------___-________ 0. 73

Amphibole-garnet-bearing contact zone__.---__-_-_____-_______.____ 1. 22

Sediments (outside contact aureole)________________________________ <. 6l

Sample & 

Decomposed sagvandite_________--_-_________--___ __________ . 65

Hydrothermal contact zone______________-_____-____________________ 1. 24

Chlorite schist in contact zone_____----_---_-_-__-__________________ <. 01

Eclogites have been reported with 0.077 ppm platinum metals (Lunde 

and Johnson, 1928) and with 0.01 ppm Ft (Noddack and Noddack, 

1931). Platinum of 0.08-0.5 ppm and Pd of 0.08-0.1 ppm are 

reported for four garnet-bearing amphibolites (Leutwein, 1939).

AVERAGE ABUNDANCES

It is difficult at present (1964) to cite meaningful figures for the 

abundance of platinum metals in different rock types. In addition 

to sampling and analytical uncertainties there probably are real 

variations of platinum metals in different geologic provinces. For 

example, comparing two mafic intrusives, the Bush veld is rich in 

platinum metals in relation to the Skaergaard. The average abundances of platinum and palladium for igneous rocks given at the 

bottom of table 11 are probably of the correct order of magnitude, 

but many more and better data are needed before the abundances 

can be established with certainty. Data are insufficient to permit 

estimates of average abundances for sedimentary or metamorphic 

rocks.

IN THE EARTH'S CRUST

Estimates of the crustal abundance of platinum metals are summarized in table 13. The later estimates are probably within one 

order of magnitude of the true abundance. Better estimates of 

crustal abundance will not be possible until more data are obtained 

on platinum-metal content of granitic rocks which make up the bulk 

of the crust.

The relative abundances of the platinum metals in the later 

estimates (table 13) are as follows:

Pd > Pt » Ir ^ Os ^ Eh « Ru.

Another figure for the relative abundance among the platinum metals 

can be obtained from the amounts recovered for industrial use. In 

table 14, production data from several sources are compared with 

estimates of relative abundance computed from the abundance figures
A16 CONTRIBUTIONS TO GEOCHEMISTRY

TABLE 13. Estimated abundance (ppm) of platinum metals in the earth's crust 

[a, significant but unknown integer]

1 _ .

2. _ 

3. . 

4..... 

5 . .

o i ^-

19

Ir

O.OOOn 

.0005 

.01 

.02 

.001

.01 

.001 

.001 

.001 

.001

Os

0. OOOn 

.0009 

.05 

.04

.05 

.01 

.001(7) 

.0001(7) 

.001

Pd

0. OOOn 

.6 

.08 

.05 

.01

.05 

.01 

.01 

.02 

.01 

.OOn

.013

Ft

O.OOOn 

1.2 

.05 

.05 

.005

.05 

.005 

.005 

.005 

.005

Eh

0. OOOn 

.01 

.01 

.01 

.001

.01 

.001 

.0001 

.001(7) 

.001

Ru

0. OOOn 

.0036 

.05 

.04

.05 

.02 

.00001(7) 

.0001(7) 

.001

Source

Clarke and Washington, 1924. 

Berg, 1929. 

Fersman, 1933. 

Schneiderhohn, 1934.

kama and Bahama, 1950. 

Anderson, 1945. 

Polanski, 1948. 

Mason, 1952. 

Vinogradov, 1956. 

Mason, 1958.

Vinogradov, 1962b.

TABLE 14. Comparison of the relative amounts of platinum metals recovered by 

industrial processes with that computed from their natural abundance

[All values in percent of total platinum metals]

Source

Mason, 1958 '. _______________

United States production, 1956-60:2

Ru

0.4

5.2

.7-3.1

1.8

.4

9.9

.05-.!

Rh

3.7

5.3

.6-4.8

9 4

.7

8.8

.3-. 5

Pd

73.5

52.6

7.5-18.8

12.4

7.3

40.0

. 3-23. 0

Os

0.4

5.2

R_9 Q

1.7

1.8

.3-1.7

Ir

3.7

5.3

3. 4-6. 5

5.0

3.4

4.7

1. 1-3. 4

Ft

18.3

26.4

68. 5-86. 2

76.7

86 4

36.6

70-84.5

' Computed from abundance figures.

5 Calculated from table 2, U.S. Bur. Mines Yearbook, 1960, v. 1, p. 889.

a Calculated from Quiring, 1962, table 16, p. 84-85.

< Quoted in Hawley, 1962, p. 122.

» Quiring, 1962, tables 17-20, p. 86-89.

of Vinogradov (1956) and Mason (1958). The tabulation shows 

that industrial recovery of platinum far exceeds the recovery of 

palladium, whereas the relative-abundance estimates would suggest 

the reverse. Probably the relative-abundance figures are in error, 

because most of the analytical data summarized in the present paper 

indicate that palladium is not as abundant as platinum in the earth's 

crust. Among the minor platinum metals, iridium is generally 

recovered in greater quantities than rhodium, ruthenium, or osmium. 

This order is consistent with the abundance figures.

IN METEORITIC MATTER

Information on the abundance of platinum metals in meteorites is 

more complete than in any other natural materials. Analyses of 

individual metals by neutron-activation and by improved wet chemical techniques are available for a variety of meteorites. Because of 

their siderophile and chalcophile character, the platinum metals are 

preferentially concentrated in siderites and the nickel-iron and 

troilite phases of chondrites. The ranges of platinum-metal content 

of siderites and chondrites are summarized hi table 15. The distri-
A17

TABLE 15. Platinum metals in individual meteorites

Element

Range (ppm)

From ToAverage 

(ppm)

References

Siderites

Ru... -..-_ ........

Overall average. _

Rh.....................

Overall average ....

Pd ... ... __ .. __ .

Overall average ....

Os.. .-.... .........

Overall average. ...

IT................ __ ..

Overall average ....

Pt.. .... 

1

2 

5.7

1

2.12 

.9

1

3.4 

1.20 

6.9

.58

2.4

.33

.3 

1.3

4

9.9 

.5 

1.86 

4.6

15

9.4

4.1

10

3.7 

6.6

3.22

17

3.3

10.3 

6.85

142

30 

29.3 

11.4

7

5.5

6.2

3.6

3.0

3.7

4.3 

3.2

3.7

2.03

6.6

4.3

1.7

3.7 

3.0

2.8

38

17 

11.0 

7.5

11.8

Hara and Sandell (1960).

Sen Oupta and Beamish (1963). 

Yavnel (1963).

Sen Oupta and Beamish (1963). 

Yavnel (1963).

Qoldberg, Uchiyama, and Brown" (1951).

Hamaguchi, Nakai, and Eamemoto (1961). 

Sen Oupta and Beamish (1963). 

Yavnel (1963).

Herr, Hoflmeister, and Langhofl (1960).

Sen Oupta and Beamish (1963).

Nichiporuk and Brown (1962). 

Sen Oupta and Beamish (1963).

Hawley (1939).

Hamaguchi, Nakai, and Kamemoto (1961). 

Nichiporuk and Brown (1962). 

Sen Gfupta and Beamish (1963) . Yavnel (1963).

Chondrites

Ru... ...............

Overall average ....

Rh.....................

Overall average. . . .

Pd.....................

Overall average ....

Os.. ...................

Overall average __

IT......................

OvArft.ll fWArncm

pt.. ...................

0.4

.7 

.6

.1

.15

.5

.73

1.7

.52

.3

.4

.32

1

.2 

1.0

0.5

1.2 

1.44

.7

.21

3.9

1.0

6.2

1.24

.6

.25

.57

10

5.6 

1.0

0.4

1.0 

.89

0.8

0.15

.19

0.2

1.0

1.0

0.91

0.9

0.4

.48

0.4

2.7

.4

0.7

Hara and Sandell (1960). 

Bate and Huizenga (1963).

Hagen (1954).

Schindewolf and Walgren (1960).

Hagen (1954).

Reed (1963).

Hagen (1954).

Rushbrook and Ehmann (1962).

Hawley (1939).

Hagen (1954).

1 Hagen, J. C., 1954, Some aspects of the geochemistry of platinum, palladium, and gold in igneous rocks 

with special reference to the Bushveld Complex, Transvaal: Massachusetts Inst. Technology [Cambridge], 

unpublished Ph. D. thesis.
A18 CONTRIBUTIONS TO GEOCHEMISTRY

bution of platinum metals in the coexisting phases in chondrites are 

listed in table 16. The data show that platinum, iridium, and 

rhodium are dominantly siderophile, and that the remaining metals 

are almost equally chalcophile and siderophile.

The most recent abundance estimates for meteoritic matter as a 

whole are listed in table 17. The disparity between estimates by 

different authors is due largely to their respective assumptions regarding the relative proportions of silicate, sulfide, and metal phases, 

although many of the basic analytic data used by the authors are the 

same. The averages calculated by the present authors are based on 

the most recent abundance values (table 15) using a ratio, chondrite: siderite=6:l (Levin and others, 1956).

TABLE 16. Distribution of the platinum metals in Fe, S, and Si phases ofchondrites

[Results given in ppm]

Element

Ru 

Kb.... 

Pd.. ------

Oa

Ir... 

Pt -

Goldschmidt 

(1954)

Pe

10

5 

9 

8

4 

20

S

9

.4 

2 

9

.4 

2

Levin and 

others (1956)

Fe

11

4.1 

3.7 

8.0

4.0 

2.0

S

4.2

1.0 

.45 

10.0

.4 

2

Hara and 

Sandell (1960)

Fe

'4.3 »5.3

S

"6.3 

 5.2

Bate and Huizenga 

(1963)

Fe

23.11 

«2.33

'1.76

«1.24

S

8 0.0323

8.0051

Si

2 0. 224 

«.222

2.170 

<.167

1 Composite Ru for 6 chondrite "finds".

2 Forest City chondrite.

> Composite Ru for 9 chondrite "finds".

«Ochansk chondrite.

' Canyon Diaplo meteorite.

TABLE 17. Recent estimates of the average content (ppm) of platinum metals in

meteorites

Source 1 Ru

2.2

4.2

1.36

2.0

1.6

Rh

0.8

1.6

.5

.6

.6

Pd

1.5

1.5

.9

.5

1.4

Os

1 Q

3.0

1 9

1.1

1.7

Ir

0.65

1 9

.4

.7

Pt

3

0

7

ft

1 Q

3.0

o q

' AssumedHcomposition, in percent, of meteoritic material, as follows:

[Present, study, computed from table 14, using chondrite : siderite=6:l]

Source

Levin, Kozolovskaya, and Starkova, chondrite: siderite-6:l..... ..... 

Silicate

78

60

85

80

Nickel-iron

15

40

g

14.5

Troilite

7

NpffHeihlfi

5
GEOCHEMISTRY OF THE PLATINUM METALS A19

In individual siderites, platinum and palladium increase with 

increasing nickel content (Hawley, 1939; Goldberg, Uchiyama, and 

Brown, 1951), whereas ruthenium decreases with increasing nickel 

content (Hara and Sandell, 1960).

Variation in concentration of various elements with gallium content 

and classification according to gallium groups has been discussed by 

Goldberg, Uchiyama, and Brown (1951) and by Levering and others 

(1957). Using Lovering's classification for meteorites of similar 

nickel content, the highest contents of palladium are reported in 

meteorites falling in group I (very high gallium), whereas the lowest 

values are reported in those of group III (intermediate gallium). 

Hawley's data on platinum follow a similar trend. No data are 

reported on meteorites of group III, but those of groups I and II 

(high gallium) have slightly higher Pt contents than those of group IV 

(low gallium) for constant nickel content. Ruthenium shows no 

consistent variation as a function of gallium content (Hara and 

Sandell, 1960).

COSMIC ABUNDANCE

Recent estimates of the cosmic abundance of the platinum metals 

are summarized in table 18. All estimates are given relative to 

Si=106 atoms rather than in parts per million, and are based on 

data from meteorites and the sun. Brown (1949) computes the 

cosmic abundances directly from these data. Brown's values for 

meteoritic matter (see table 17) disagree with those of other authors, 

because his assumptions regarding the composition of meteoritic 

matter are so different from those of other authors. Other authors, 

using essentially the same data, have modified the estimates of 

cosmic abundance to fit various theories of nucleogenesis. A good 

discussion of the assumptions that go into the modified estimates 

is given by Cameron (1959). There is generally good agreement 

among the three most recent estimates which indicate that the platinum 

metals fall in the following order of decreasing cosmic abundance:

Pt>Ru>Pd«Os>Ir>Rh

Table 18. Recent estimates of cosmic abundance of the platinum metals 

[Atoms per million atoms of 81]

Eeference

"RrrtTim (\ Q4Q^ 1

Suess and Urey (1956) ^. .......... ........ . ... ........

Aller (1961) ».. . 

Ru

9.3

1.5

.9

.9

Eh

3.5

.2

.15

.2

Pd

3.2

.7

.7

.6

Os

3.6

1.0

.6

.8

Ir

1.4

.5

.5

Pt

8 7

1

0

1

0

1

0

1 Data from meteorites and sun.

2 Values obtained by adjusting empirical solar and meteoritic abundances to conform to various theories 

of nucleogenesis.
A20 CONTRIBUTIONS TO GEOCHEMISTRY

SUGGESTIONS FOB FUTURE STUDY

It is evident in the preceding that many more data are needed 

to understand adequately the geochemistry of the platinum metals. 

Platinum-metal contents of abundant rock types, particularly granites, 

are needed to improve the estimates of crustal abundance. Because 

of the uneven distribution of platinum metals in rocks, future analyses 

should be based on samples of large masses of rock. Complete 

analyses for six platinum metals are badly needed to estimate accurately the relative abundances of platinum metals in the crust. 

Detailed study of the mineralogy of the platinum metals is just now 

beginning. The electron microprobe should be used to determine the 

limits of solid solution of platinum metals in natural alloys, the 

composition variations in platinum-metal compounds, and the extent 

to which trace amounts of platinum metals in rock-forming minerals 

are present as discrete inclusions or as substituting ions. Finally, 

we know little about the actual behavior of the platinum metals in 

magmatic processes. Experimental work on solubilities of platinum 

metals and platinum-metal complexes is needed to understand the 

mode of transport of platinum metals in ore-forming solutions and 

the role played by the platinum metals in magmatic crystallization.

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GEOCHEMISTRY OF THE PLATINUM METALS A23

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A24 CONTRIBUTIONS TO GEOCHEMISTRY

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O