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HARPER’S LIBRARY _of_ LIVING THOUGHT
[Illustration: (publisher colophon)]
[Illustration:
DIAMONDS
BY
SIR WILLIAM
CROOKES
HARPER &
BROTHERS
LONDON & NEW YORK]
[Illustration: THE CULLINAN DIAMOND.
From a photograph by the Author. (See pages 76-79.)
Frontispiece.]
·DIAMONDS·
BY
SIR WILLIAM CROOKES
LL.D., D.Sc., F.R.S.
Foreign Sec. R.S., Hon. LL.D. (Birmingham), Hon. Sc.D. (Camb.
and Dubl.), Hon. D.Sc. (Oxon. and Cape of Good Hope); Past Pres.
Chem. Soc., Brit. Assoc., Inst. Elect. Eng., Soc. Psych. Res.;
Hon. Mem. Roy. Phil. Soc. Glasgow, Roy. Soc. N.S.W., Pharm. Soc.,
Chem. Metall. and Mining Soc. of South Africa, Amer. Chem. Soc.,
Amer. Philos. Soc., Roy. Soc. Sci. Upsala, Deutsch. Chem. Gesell.
Berlin, Psychol. Soc. Paris, “Antonio Alzate” Sci. Soc. Mexico.
Sci. Soc. Bucharest, Reg. Accad. Zelanti, Aci Reale; Corresp.
Inst. de France (Acad. Sci.), Corresp. Mem. Bataafsch Genoots.
Rotterdam, Soc. d’Encouragement pour l’Indust. Paris, For. Mem.
Accad. Lincei Rome.
WITH 24 ILLUSTRATIONS
LONDON AND NEW YORK
HARPER & BROTHERS
45 ALBEMARLE STREET, W.
1909
TO MY WIFE
MY COMPANION AND FRIEND OF
FIFTY-FOUR YEARS.
TO HER JUDGMENT AND ADVICE I OWE MORE
THAN I CAN EVER REPAY
AND TO HER I DEDICATE THIS BOOK.
PREFACE
The following pages are based on personal observations during two
visits to Kimberley, in 1896 and 1905, and on personal researches
on the formation and artificial production of diamonds. In 1896 I
spent nearly a month at Kimberley, when Mr. Gardner F. Williams,
the General Manager of the De Beers Consolidated Mines, and the
managers of neighbouring mines, did their utmost to aid in my
zealous quest for reliable information. They gave me free access
to all workings above and below ground, allowed me to examine at
leisure their stock and to take extracts from their books. I had
exceptional opportunities of studying the geology of the Diamond
and of noting the strange cataclysmal facts connected with the
birth, growth, and physics of the lustrous stones.
In 1905 with my wife I returned to Kimberley. We were members of
the British Association which held its meeting that year in South
Africa. I was asked to give one of the Association lectures at
Kimberley and it was natural for me to discourse “On Diamonds.”
During our stay we were the guests of Mr. Gardner Williams.
Returning to England after the visit of 1896, I gave two
lectures on Diamonds at the Imperial Institute and one at the
Royal Institution. These lectures, and the lecture delivered at
Kimberley, in 1905--hitherto only privately distributed--form
the basis of the present volume. On each visit I took abundant
photographs, many of which I now reproduce. A few are copied
from plans lent by Mr. Gardner Williams and one or two are from
photographs purchased at Kimberley.
In obtaining statistical information of the Diamond industry, I owe
much to the Annual Reports of the De Beers Company. I have also
quoted freely from Reunart’s valuable book on _Diamonds and Gold in
South Africa_; and I render my acknowledgments to the authors of
the following papers and memoirs.
_On a Visit to the Diamond Fields of South Africa, with Notices of
Geological Phenomena by the Wayside._ By John Paterson, Esq., M.A.
_On the Mode of Occurrence of Diamonds in South Africa._ By E. J.
Dunn.
_On the Origin and Present Position of the Diamonds of South
Africa._ By G. G. Cooper, Esq., of Graaf Reinet.
_On the Character of the Diamantiferous Rock of South Africa._
By Prof. N. Storey Maskelyne, F.R.S., Keeper, and Dr. W. Flight,
Assistant in the Mineral Department, British Museum.
_Further Notes on the Diamond Fields of South Africa._ By E. J.
Dunn.
_Notes on the Diamond Fields of South Africa, 1880._ By E. J. Dunn.
_Analogies between the Diamond Deposits in South Africa and those
in Meteorites._ By M. Daubrée.
_Notes on the Diamond-bearing Rock of Kimberley, South Africa._ By
Sir J. B. Stone, Prof. T. G. Bonney, and Miss Raisin.
_Notes on the Diamond Rock of South Africa._ By W. H. Hudleston.
_The Parent Rock of the Diamond in South Africa._ By the Reverend
Professor T. G. Bonney.
The Presidential Address, by Grove Carl Gilbert, to the Geological
Society of Washington, on _The Origin of Hypotheses. Illustrated by
the Discussion of a Topographical Problem._ 1896.
_Le Four Electrique._ By Henri Moissan. 1897.
_The Diamond Mines of South Africa._ By Mr. Gardner F. Williams.
(In this publication the story of the rise and development of the
industry is exhaustively narrated.)
_British Association, South African Meeting, 1896, Kimberley
Handbook._
_The Meteor Crater of Canyon Diablo, Arizona; its History, Origin,
and Associated Meteoric Irons._ By George P. Merrill. 1908.
In the present volume I have tried to give some idea of the
underground wonders of the Kimberley mines. I have pictured the
strenuous toil of the men who bring to the surface the buried
treasures, and I have given some idea of the skill and ingenuity
with which their labours are controlled. I have done my best to
explain the fiery origin of the Diamond, and to describe the
glowing, molten, subterranean furnaces where they first begin
mysteriously to take shape. I have shown that a diamond is the
outcome of a series of Titanic earth convulsions, and that these
precious gems undergo cycles of fiery, strange, and potent
vicissitudes before they can blaze on a ring or a tiara.
I am glad to have paid these two visits to South Africa. I always
recall with interest the dusky smiling natives at work and at
play. I am glad to have seen that Arabian Nights vision, the
strong-room of the De Beers Company. Above all, I have vividly
graven on my heart the friendly welcome, and the innumerable acts
of kindness shown us by our able, energetic, and enterprising
Colonial fellow-countrymen.
W. C.
CONTENTS
CHAPTER PAGE
I. PRELIMINARY 1
II. KIMBERLEY AND ITS DIAMOND MINES 14
III. KIMBERLEY MINES AT THE PRESENT DAY 34
IV. COLLECTING THE GEMS 55
V. THE DIAMOND OFFICE 73
VI. NOTEWORTHY DIAMONDS 76
VII. BOART, CARBONADO, AND GRAPHITE 81
VIII. PHYSICAL AND CHEMICAL PROPERTIES OF
THE DIAMOND 89
IX. GENESIS OF THE DIAMOND 115
X. THE NATURAL FORMATION OF THE DIAMOND 127
XI. METEORIC DIAMONDS 134
INDEX 141
LIST OF PLATES
The Cullinan Diamond, from a photograph by the
Author (see pp. 76-79) _Frontispiece_
FIG. FACING PAGE
1. River Washings at Klipdam 10
2. Plan of the Kimberley Diamond Mines 10
3. Kimberley Mine. The “Pipe” 18
4. Section of Kimberley Mine 18
5. Wesselton Diamond Mine. Open Workings 34
6. De Beers Compound 40
7. De Beers Mine. Underground Workings 40
8. De Beers Washing and Concentrating Machinery 48
9. Sorting Concentrates for Diamonds. De Beers 54
10. De Beers Diamond Office. 25,000 carats 72
11. De Beers Diamond Office. The Valuators’ Table 72
12. A group of large Diamond Crystals 76
13. Some Historic Diamonds 80
14. Crystalline forms of native Diamonds 86
15. Triangular Markings on natural face of a Diamond
Crystal 88
16. Triangular Markings artificially produced on a
Diamond Crystal 88
17. Diamond-cut Glass and Shavings 98
18. Diamonds in Röntgen Rays. A. Black Diamond
in gold frame. B. Pink Delhi Diamond.
C. Paste Imitation of B. 98
19. Curve of Vapour Pressure of Carbon _page_ 113
20. Moissan’s Electric Furnace 116
21. Artificial Diamond made by the Author from
molten iron 120
22. Moissan’s Artificial Diamonds 120
23. Diamonds from Canyon Diablo Meteorite 138
DIAMONDS
CHAPTER I
PRELIMINARY
From the earliest times the diamond has fascinated mankind. It
has been a perennial puzzle--one of the “riddles of the painful
earth.” It is recorded in _Sprat’s History of the Royal Society_
(1667) that among the questions sent by order of the Society to
Sir Philiberto Vernatti, Resident in Batavia, was one inquiring
“Whether Diamonds grow again after three or four years in the same
places where they have been digged out?” The answer sent back was,
“Never, or at least as the memory of man can attain to.”
In a lecture “On Diamonds,” fifty years ago,[1] Professor Maskelyne
said, “The diamond is a substance which transcends all others in
certain properties to which it is indebted for its usefulness in
the arts and its beauty as an ornament. Thus, on the one hand, it
is the hardest substance found in nature or fashioned by art. Its
reflecting power and refractive energy, on the other hand, exceed
those of all other colourless bodies, while it yields to none in
the perfection of its pellucidity.” He was constrained to add, “The
formation of the diamond is an unsolved problem.”
Diamonds are found in widely separated parts of the globe. In the
United States they have been found in Arkansas, where the work of
testing the deposits is now going on steadily and quietly. The
general geology and petrography of the area and the weathering of
the peridotite are described in a paper read before the American
Institute of Mining Engineers by Messrs. Kunz and Washington. In
tests made with a diamond drill the peridotite was proved to
depths of 200 feet. The green and yellow grounds underlying the
layer of black, sticky soil are found to extend down 40 feet in
places, and are estimated to average 20 feet in depth over the
area. The outcrop of the peridotite is estimated to cover about
40 acres, and may be larger. Some 540 diamonds have been found,
with an aggregate of 200 carats. The largest stone weighs about
6·5 carats, though the average size compares favourably with the
general run of most of the South African mines. There is a large
proportion of white stones, many of which are free from flaws and
are very brilliant. The genuineness of the occurrence of diamonds
in their matrix is again proved, one stone having been found
imbedded in the green ground at a depth of 15 feet. This peridotite
has the form of a volcanic pipe, and therefore its outcrop is
limited to one place.
In California authentic finds of diamonds are recorded in Butte
County, especially at Cherokee, above Orville. These diamonds,
however, have come from alluvial deposits and have been found
generally in washing for gold. As yet no authenticated discovery of
diamond in its original matrix in California is recorded.
In Brazil the diamond industry has been increasing of late years,
and the old mines in the Diamantina country are being worked by
American capital and by the American methods which have proved so
successful at De Beers. It is estimated that the annual value of
the diamonds exported from Brazil amounts to over £800,000, but
it is impossible to arrive at accurate figures owing to the large
quantities smuggled out of the country to avoid payment of the
export tax.
British Guiana produces a small quantity of diamonds, mostly,
however, of small size. Between January and September, 1907, 1564
carats were exported.
Indian diamonds chiefly come from the states of Panna, Charkhari,
and Ajaigarh. In 1905 India exported 3059 carats, valued at £5160.
CAPE COLONY
It is a standing surprise to the watchful outsider how little
attention is bestowed on some of our colonies. For instance, to
the Cape Colony, comprising vast, varied, and productive regions,
we have till recently manifested profound ignorance and consequent
indifference. When the Cape Colony was first incorporated with
the Empire, it was pronounced “a bauble, unworthy of thanks.” Yet
before the Suez Canal and the Waghorn overland route to India, the
Cape, as commanding our road to India, Australia, and China, had a
special importance. Even now it presents an alternative route which
under conceivable circumstances may be of capital moment.
The high grounds above Cape Town are rich in medicinal
health-giving waters. The districts where these springs occur
are high-lying, free from malaria, and admirably adapted for the
restoration of invalids. It needs only some distinguished power to
set the fashion, some emperor, prince, or reigning beauty to take
the baths and drink the waters, and the tide of tourists would
carry prosperity to Aliwal North, Fraserburg, Cradock, and Fort
Beaufort.
South Africa, as I shall endeavour to show in detail, is the most
important source of diamonds on the earth, and ranks with Australia
and California as one of the three great gold-yielding regions. But
the wealth of South Africa is not only in its gold and diamonds.
The province of Natal contains more coal than Britain ever owned
before a single bucket had been raised, and the beds extend over
the Orange River Colony, whilst valuable iron ores exist also in
large quantities.
In the year 1896 I spent nearly a month at Kimberley. Mr. Gardner
F. Williams, General Manager of the De Beers Consolidated Mines,
and the Managers of neighbouring mines, did their utmost to assist
me in my inquiries and to ply me with valuable information. I had
full access to all the workings, above and below ground, and was
able to examine at leisure their stock and take extracts from their
books.
Again, in the year 1905, I paid another visit to Kimberley as the
guest of Mr. Gardner Williams on the occasion of the meeting of the
British Association in South Africa.
RIVER WASHINGS
Besides the matrix mines, where the stones are found in pipes
supposed to be of volcanic origin, the alluvial deposits on the
Vaal River are of considerable importance. The terraces and gravels
along the Vaal River for about 200 miles have been worked for
diamonds, the deposits sometimes extending several miles on each
side of the river, and varying from a few inches to 40 or 50 feet
in thickness. The diamonds are found almost everywhere through the
gravel deposit.
Before describing the present mode of diamond extraction followed
in the important mines, I will commence with these “River
Washings,” where, in their primitive simplicity, can be seen the
modes of work and the simple machinery long since discarded in
the large centres of the industry. The drift or so-called “river
washings” present a very interesting phase of diamond industry. The
work is carried on in the primitive fashion adopted in the early
days of diamond discovery, every man working on his own little
claim, assisted by a few natives, and employing primitive machinery
(Fig. 1). The chief centre of the Vaal River washings is about 30
miles to the north-west of Kimberley, at a place called Klipdam
No. 2. There was originally a Klipdam a few miles further, and
here the miners congregated, but the exhaustion of their claims
made them migrate to others not far off and reported to be richer.
Here, accordingly, they re-erected their iron houses and called it
Klipdam No. 2.
It is a mistake to speak of “river washings.” The diamantiferous
deposits are not special to the old or recent river bed, but appear
to be alluvial deposits spread over a large tract of country by
the agency of water, which at some period of time subsequent to
the filling up of the volcanic pipes planed off projecting kopjes
from the surface of the country and scattered the debris broadcast
over the land to the north-west of Kimberley. The larger diamonds
and other heavy minerals would naturally seek the lowest places,
corresponding with the river bed, past and present. The fact that
no diamonds are found in the alluvial deposits near Kimberley
may perhaps be explained by supposing that the first rush was
sufficiently strong to carry the debris past without deposition,
and that deposition occurred when the stream slackened speed. At
Klipdam No. 2 the diamantiferous earth is remarkably like river
gravel, of a strong red colour--quite different from the Kimberley
blue ground--and forms a layer from 1 to 8 feet thick, lying over
a “hard pan” of amygdaloidal trap, the melaphyre of the Kimberley
mines.
[Illustration: FIG. 1. RIVER WASHINGS AT KLIPDAM.]
[Illustration: FIG. 2. PLAN OF THE KIMBERLEY DIAMOND MINES.
To face p. 10.]
When I was at Klipdam the miners had congregated at a spot
called “New Rush,” where some good finds of diamonds had been
reported. The gravel is dug and put into a machine resembling
the gold miner’s dolly, where it is rocked and stirred by rakes,
with a current of water flowing over it. Here all the fine stuff
is washed away and a rough kind of concentration effected. The
residual gravel is put on a table and sorted for diamonds--an
operation performed by the master. At one of the claims where
work was proceeding vigorously I asked the proprietor to let
me be present at the sorting out, as I should like to see river
diamonds. He willingly consented, but no diamonds were to be found.
On my expressing regret, he said he had not seen a diamond for a
fortnight! I remarked that the prospect was rather a poor one,
but he told me that a fortnight before he picked out one worth
£300, “and that,” he said, “will pay for several weeks’ wages of
my boys.” This is the kind of speculative gambling that goes on at
the river diggings. The miner may toil fruitlessly for months, and
then come across a pocket of stones, where they have been swept by
some eddy, by which he will net several thousands. Diamonds from
the “river washings” are of all kinds, as if contributed by every
mine in the neighbourhood. They are much rolled and etched, and
contain a good proportion of first-class stones; they are of very
good quality, as if only the better and larger stones had survived
the ordeal of knocking about. Diamonds from the drift fetch about
40 per cent more than those from Kimberley; taking the yield of the
Kimberley and De Beers mines as worth all round, large and small,
26s. 6d. a carat, those from the drift are worth 40s.
As a rule the better class of natives--the Zulus, Matabeles,
Basutos, and Bechuanas--when well treated, are very honest and
loyal to their masters. An amusing instance of the devotion of a
Zulu came to my knowledge at Klipdam. He had been superintending
a gang of natives on a small claim at the river washings. It
yielded but few stones, and the owner--my informant--sold the
claim, handing over the plant and small staff, our friend the
Zulu remaining to look after the business till the new owner took
possession. In the course of a few months the purchaser became
dissatisfied with his bargain, not a single diamond having turned
up since the transfer. One night the Zulu came to his old master
in a mysterious manner, and laying a handful of diamonds on the
table, said, “There, Baas, are your diamonds; I was not going to
let the new man have any of them!”