The diamond is widely dispersed over the earth, and undoubtedly occurs in countries where its existence is not now suspected. The difficulty of detection has restricted its geographical area in history, yet enough is known to regard its deposition as almost universal, or at least quite as frequent as that of gold. In some countries the deposits are very limited, while in others, like those of Africa, Brazil, and India, they stretch away over immense distances.
We will proceed to give brief descriptions of the well-known diamond districts, and mention others but little known to commerce or the mineralogists. For more extended accounts of the historical mines we must refer the reader to the works of the authors quoted in our text. We will commence with those of Asia.
The diamond fields in India are very extensive, and occur everywhere among the hills of the great range that extends from Cape Comorin through the whole of Bengal for a distance of several hundred miles and with an average breadth of fifty miles.
How long these mines have been known to man must always remain a matter of conjecture; but it is nevertheless certain that the famous mines have been discovered within the past thousand years, and probably a much less period of time. It is stated that many of the gem districts along this range have not been explored carefully, and that the kingdoms of Golconda and Visapour alone have supplied most of the gems known in India. And it is also related that none of these localities have been scientifically mined or surveyed with a view to thorough development.
The most ancient of the diamond mines in India are supposed to be those of Soumelpour, near the river Gonet, a tributary of the Ganges; but the celebrated mines of Golconda and Raolconda have been known only since the fifteenth and sixteenth centuries.
The richest mine of India, and the most extraordinary of any yet discovered in the world, is that known by the name of Gani, or Couleur. It is situated under a plain at the foot of a mountain about seven days’ journey west of Golconda, and was discovered by accident about the middle of the sixteenth century.
A native digging the earth to sow millet threw up a bright, clear crystal of twenty-five karats. It was soon recognized to be a diamond, and crowds of Hindoos flocked to the fields to reap the most wonderful harvest of gems yet known. A vast number of large gems were obtained, and among them the Great Mogul, which weighed in its rough condition seven hundred and ninety-three karats. The gems of this mine were remarkable for their large size, but they were not of the clearest and purest water, the color and lustre of the stone seeming to partake of the quality of the earth composing the matrix.
This idea, which prevails among the miners in other gem districts in India and also in other countries, lends support to the belief that the diamonds were formed in the strata of gravel where they are now found, and not in the hard crystalline rocks and afterwards set free by disintegration.
The matrix of these mines, as well as of all the others in different parts of the world, is essentially the same; and consists of rolled or broken masses of quartz, mixed or united with sand or earth impregnated with a ferruginous oxide. Amongst this conglomerate, or immediately below it, mixed with clay, the diamonds are found, and generally unattached to any substance.
The earliest and best accounts of the mines of Golconda are to be found in the narrative of Tavernier, who visited them in the middle of the seventeenth century. At this time they were in prosperous condition and furnished occupation to many thousand men. There were but four mines then worked in Hindostan, and more than sixty thousand miners were employed at the mine of Gani, or Couleur, alone. About thirty years after the last visit of Tavernier, the Earl Marshal of England, who had previously examined the diamond mines on the coast of Coromandel, visited those in Bengal. He found that diamond mines occurred everywhere along the slope of the hills extending through the country; but that very few of them were worked, and that nearly all of the diamonds then supplied to commerce were obtained from the kingdoms of Golconda and Visapour. He gives descriptions of twenty-three mines in Golconda and fifteen in Visapour.
The most famous of these at that time was called Currure, and was worked by the king for his own use. Several very large gems are said to have been found at this locality. It is related that a Portuguese gentleman from Goa, having received permission to explore a part of this mine, had the good fortune to discover a diamond of two hundred and six karats, which so overjoyed him that he erected a large stone over the spot with an inscription in Hindoo commemorative of the event.
Near this place there was another famous mine which yielded stones of fine form and water, occurring in black earth, which is regarded in India as a singular formation. In all the mines of Visapour the diamonds are found in red and yellow earth, and this is generally the color of the matrix elsewhere.
William Methold visited the mines of Golconda at a later period, and relates that at that time they gave employment to about thirty thousand laborers. The means for exploration were then exceedingly simple, and no mechanical contrivances were adopted for excavating the pits or bailing out the water. Shafts were rudely sunk in the earth to the depth of sixty or seventy feet, and the cascalho found at even that depth. It appeared to be reddish, mixed with white and yellow chalk, and was rich in diamonds. Rarely, stones of one hundred and twenty to two hundred karats were found, while those of ten to fifteen karats were quite abundant; but by far the greater number were so minute that it required from eight to twenty of them to weigh a karat.
Within the present century Dr. Buchanan and Mr. Voysey visited the mines of India, and have left interesting and accurate descriptions of their examinations and observations.
The famous mine of Pannah was examined in 1813, and found to be situated in a table-land of great extent a thousand feet or more above the Gangetic plain. The whole plain, wherever the gravelly formation appeared, afforded diamonds at various depths ranging from six feet to twenty-four. Many mines were worked in beds or borders of rivers because they were easy of access, and the lazy natives lacked the ability and means to explore the adjacent plains, which abounded in diamonds, but were destitute of the water required for washing the gravel.
The effect of the Brazilian discovery and its yield of several tons of diamonds was severely felt in Hindostan, and many of its mines were stopped in consequence. Yet there is abundant virgin territory left in India for future successful exploration, if conducted scientifically and with ample means.
The natives, with their rude methods of mining, generally ceased operations when the deposit required the removal of twenty-four feet of superincumbent soil. Hindoo labor, also, though apparently very cheap, is in reality costly when we come to compare their slow and feeble results to the efforts of well organized and conducted operations. Hence the diamond has always been a costly gem in Hindostan, and it is worth more in that country at the present time than in Europe.
Concerning the widespread idea of the reproduction of diamonds in India we will make only a brief allusion at the present time.
This theory does not seem to be of a very recent date, for the Portuguese traveller Garcias, who had been physician to the Viceroy at Goa in the early part of the sixteenth century, and who visited the mines, has left in his treatise published in 1565, some curious notes on the rapid generation of diamonds at that time. And he affirms that the soil a few feet below the surface will, in the interval of two or three years, produce diamonds again; but he also admits that the largest gems are only found at much greater depths.
Mr. Voysey, who examined the principal mines in Southern India in 1821, was also assured by the miners of this reproduction; and from his investigations he was led to adopt similar views.
Dr. Buchanan in 1813 visited the famous Pannah mine, and these views then prevailed at that locality. He examined the diamond-bearing earth, but observed nothing very peculiar in its formation. It seemed to be very red, and characterized by pebbles stained by iron and a great variety of quartz in broken fragments, chiefly white in color, or stained red in places, or dotted with black spots.
The miners who were then operating the mines assured the Doctor “that the generation of diamonds is always going forward, and that they have just as much chance of success in searching earth which has been fourteen or fifteen years unexamined as in digging in what has never been disturbed; and in fact,” he says, “I saw them digging up earth which had evidently been before examined, as it was lying in irregular heaps as thrown out after examination.”
Borneo is thought to be rich in diamonds, but concerning the extent and productiveness of the placers but little definitely is known. The island has long been known as abounding in the gem, but travellers and mineralogists have been prevented from exploring it by a variety of causes, chiefly arising from opposition of the native rulers and difficulty in penetrating into the interior of the country where the mines are found.
Tavernier was desirous of visiting these mines, but was dissuaded from going by these supposed or fancied difficulties, and the fact that the Queen at that time forbade the exportation of the gem. Therefore we have to regret the absence of the report which this able and truthful traveller would have made if he had visited those regions.
The Borneo diamonds are reported to be the best in the world, and to owe their excellence to a faint steel-like tinge and a very vivid adamantine flash. We are inclined to think, however, that diamonds of this description may be found in various countries, and that commerce assigns their locality to Borneo as a matter of convenience and trade.
Borneo is yet a terra incognita, and its features have not yet been made known to geography or even commerce. The second island in size in the world, and itself almost a continent, it presents a vast field to the explorer, with its broad prairies, immeasurable forests, deep and impenetrable jungles, interspersed with lofty ridges of mountains. Its mineral wealth is undetermined, but enough is known to found the belief that the island is one of the richest in this respect on the globe.
Concerning the diamond mines we have but imperfect accounts and none of very recent dates. However, it is known that the character of the mines is the same as that of India and elsewhere, and that the gems are found in a gravelly stratum at various depths below the surface. The best of these mines are said to be situated along the river Lavi, near Sukkademia, and to be worked in a rude manner by the Malays and Chinese. Mines on the northwest coast of the island have been worked extensively, but it is reported that no large diamonds have been discovered there. The Colonial Secretary, Mr. Low, states that the gems are found in the greatest quantities in Sango, Landak, and Banjarmassin, and that the stones, although of small size, are of the purest water.
The quantity of diamonds afforded by Borneo is not exactly known, but a recent writer in the Journal of the Geographical Society of London gives it as about two thousand karats annually. It is also stated by various authorities that the mines of the island have never yet yielded a diamond of thirty-six karats in weight.
If these reports are correct, how can we explain the accounts of the great diamond belonging to the Sultan of Mattan, which may be found in the History of Java, by Sir Stamford Raffles, and also in the Memoirs of the Batavian Society?
The famous mines of Brazil, which gave rise to a new era in the commerce and history of diamonds, were discovered by accident. And we are not aware of an instance of the discovery of a single diamond district or region of country, with the exception of the Urals, which can be ascribed to the results of scientific research. Even the wonderfully rich mines of the Province of Bahia in Brazil were first made known by a slave who noticed the similarity of the soil to that of the diamond mines of Minas Geraes, where he had formerly worked.
In 1727 a Portuguese by the name of Lobo, while visiting the gold mines of the Sierra do Frio, a desolate country about four hundred miles north of Rio Janeiro, noticed some bright crystals of stone which the ignorant miners picked up from time to time and treasured as trifles. Gathering a number of them, he submitted them to some Dutch traders, who informed him as to their valuable character. The Dutch at once contracted with the Brazilian Government for all of the rough diamonds that might be found, and for a long time controlled the trade. The mines where the gems were first discovered were situated in the midst of a desolate country destitute of vegetation and of considerable elevation above the level of the sea. Since this period other mining districts have been discovered, and it is now ascertained that the whole of the vast territory situated between the twelfth and twentieth parallels of latitude and extending even to Matto Grosso, a thousand miles distant, belongs to the gem-bearing formation.
This vast space of territory has not been examined scientifically, and but little is known of its condition except that it is diamond yielding. Since their discovery the mines have been worked with more or less activity with slave labor under the direction of companies of large capital. Skilled labor with the modern appliances of science has not yet been employed in these mining districts. And the condition of the country, its laws, and the controlling power of the diamond corporations, will render the application of scientific skill a difficult and hazardous task. The explorations are conducted in a primitive manner during the dry season, which lasts from April to October. They are made generally in the beds of the streams which have been dried up by the summer’s drouth. Rivers are sometimes diverted from their natural course, and their gravelly beds completely removed to sheds on the banks to await the rainy season, when water, which is required for washing, will be in abundance. The cascalho, a name given to the peculiar gravel, composed of quartz fragments mixed with sand and clay united with a ferruginous cement, which contains the diamonds, is then placed in shallow troughs, and a stream of water directed upon it until it is well cleansed, when it is removed and dried in the sun. The dried residue is then carefully searched for diamonds, and it is not always easy to distinguish them among a great variety of pebbles, of which the débris is chiefly composed.
Some of the diamond mines were of great extent and required many laborers to conduct the operations. That of Mandanga employed twelve hundred slaves in its excavations alone, besides many free persons engaged in other duties. The yield of the Brazilian mines at first was enormous, and one thousand one hundred and forty-six ounces of the precious gem were shipped to Lisbon in one year. The vast quantities of the gem thrown upon the markets brought the price of them down to five dollars per karat.
Consternation speedily spread among the diamond dealers all over the world; and many of them, believing that the gems would soon be as common as transparent quartz, declined to invest largely, even at these low prices. But a panic was checked by the prompt action of the Brazilian Government, in claiming the working of the mines as a royal monopoly, and also regulating the supply. In this condition of affairs the working of the mines and the trade remain at the present day; but the African discoveries and free explorations may change this restriction and monopoly if the Cape fields continue to yield their present supply. According to the estimates of Baron d’Eschwège, the quantity of diamonds obtained from the Brazilian mines under the Government restrictions averaged between 1730 and 1814 thirty-six thousand karats annually, the cost of which amounted to nearly four dollars per karat.
From a variety of causes the supply gradually diminished until about the year 1830, when the diminution was so great, coupled with the increased cost of exploration, that the rough stones cost eight dollars per karat. In 1843 the discovery of the Bahia mines increased greatly the yearly supply, which was then about thirty thousand karats. For two years after the discovery of the Sincora mines the supply amounted to six hundred thousand karats. But the great distance of the mines from the large towns and the coast, the fearful malaria which prevailed in the district, together with the difficulty of obtaining supplies, have prevented the working of the mines to any great extent; and in consequence the supply in 1852 sank to one hundred and thirty thousand karats. In 1732 the price of the rough gem was five dollars per karat, but in three years after it rose to about eight dollars per karat, and remained at that figure as late as 1742.
The Brazilian diamonds are generally very small compared with those yielded by some of the India mines, like that of Gani, which produced a great many gems of ten to forty karats weight. Of the Brazilian yield it was found by Professor Tennant that out of one thousand diamonds, one half weighed less than half a karat; three hundred, less than one karat; eighty, one and a half karats; one hundred and nineteen varied from two to twenty karats, and only one reached twenty-four karats.
Brazil still exports annually diamonds to the value of several millions of dollars, but the exploration has probably been checked by the influx from South Africa and the consequent fall in prices.
Out of the immense number of gems yielded by these mines,—the district of Minas Geraes is said to have produced two tons in weight,—it is strange that more large gems have not been found.
Quite a number of diamonds exceeding fifty karats have been discovered, and several over one hundred karats, the largest being known as the Star of the South, which weighed two hundred and fifty-four karats. This fine gem was found in 1853 in the mines of Begagem by a negress. It was in the form of a dodecahedral crystal. Another fine gem, called the Abaethe, was found in 1797 in the alluvium of the river Abaethe. Three convicts, banished into the interior of the savage country, wandered about from thicket to thicket and mountain to mountain, in hope of discovering some treasure that would restore them again to their friends. After six years of weary wanderings and severe privations they at length stumbled upon a diamond of one hundred and five karats in the bed of the river above named. They ventured to return to the inhabited regions and confided their good fortune to a priest. He took them at once to the Governor of Villa-Rica, who suspended the sentence of the convicts and sent the priest to Rio Janeiro with the gem.
A frigate was despatched with the treasure and the clergyman to Lisbon. The King, delighted with his acquisition, fully pardoned the convicts and advanced the priest to a high rank in his profession.
Many attempts have been made to trace the diamonds of Minas Geraes to primitive and unbroken rocks on the more elevated plateaux or even among the more distant mountains. And sometimes the gems have been found in cascalho at a great elevation, or perhaps in crevices of the sandstones; and hence the idea has arisen that the solid matrix has been found. The cascalho is the true matrix, whether found in the lowlands or on the mountain peaks. The color of this conglomerate is not uniform and varies in many districts. At the rich St. Antonio’s mine it is of a dark gray; at the Veneno it is of a light ochre with lumps cemented with ferruginous oxide; in the Pitanga mine it is of a light gray and almost white, and contains but few diamonds, but of the finest quality. The observer is sometimes led to believe that the abundance of the ferruginous oxide is evidence of the abundance of gems, and this fact is also noticed in the famous mines of Ceylon, where, however, the diamond does not occur.
Concerning the accounts of finding the diamonds in Brazil in their native rock, as described by Claussen and later still by Redington, we are not yet willing to give full credence any more than to the stories of diamonds having been found in the “old rock” in India. We have no doubt of the gem having been found in what appears to be a soft sandstone, but which is in reality a secondary product like the heterogeneous cascalho. And we can conceive this sandstone-like deposit to be formed at the bottom of lagoons under like conditions which gave origin to the conglomerate.
Claussen published in the Bulletins of the Academy of Sciences and Belles-lettres at Brussels, in 1841, an interesting account of his observations while searching for a matrix of the diamond.
He affirms that the gems are found at the mines of Grammagon in beds of a soft sandstone, which he calls a psammite sandstone, and which resembles the itacolumite, which is much harder. He also describes several specimens in which the gems are embedded in the sandstone, but admits that they are not very common. The same writer mentions instances where they are said to have occurred between plates of mica like the flattened garnets. Furthermore, he states that the crystals found in the itacolumite are rounded octahedrons and those found in psammite sandstone are perfect octahedrons.
Claussen, although he believed the itacolumite to be the matrix of the gem, was unable to explain its total absence in places where the itacolumite was greatly developed. He was also forced, when tracing the origin of the cascalho, to admit the existence of a secondary itacolumite posterior to the transition formation.
It is interesting as well as perplexing to follow the multitude of views expressed by mineralogists when attempting to explain the formation of the diamond. Most of them are determined to give the gem an ancient origin, and insist upon the action of plutonic forces upon dioritic veins. Humboldt maintained that the gems of the Ural Mountains had a geological relation to the carboniferous dolomite of Adolfskoi as well as to augitic porphyry. But Verneuil and Murchison, examining the mines, found the alluvia which contained the diamonds had no carbon; therefore the hypothesis was incorrect, and the matrix of the stone must be sought in another direction. The mines of Brazil have been examined during a century past by a number of geologists and amateurs like Mawe, Martins, St. Hilaire, Claussen, Eschwège, Burton, Hartt, and others; and to their works we must refer the reader for extended descriptions of the geological features of the country and the peculiarities of the gem mines.
In the recent exploration of the diamond fields by Professor Hartt, the Professor decidedly opposes the views of Claussen by saying, “I do not believe that the diamond ever occurs in the true palaeozoic itacolumite in Brazil, but that it is derived from the tertiary sandstones.” After casual examination of the diamond-bearing sands of the mines in Bahia, he is also led to believe that they have resulted from the disintegration of Chapada sandstones; and he regrets that they have never been critically examined, for he thinks that the mystery of the origin of the diamond may be solved from their study.
However, from the multitude of hypotheses to which the study of the subject has given rise, we find nothing to shake our confidence in the belief of the formation of the diamond in the secondary gravel beds where they are now found.
Shortly after the opening of the Bahia mines, black, brown, and even clay-colored pebbles were found associated with the transparent diamonds in the cascalho. These pebbles were of various sizes, generally quite small, but sometimes appearing in masses as large as one thousand karats. Their nature was not at first recognized, and they were thrown aside with all other stones of little or no value. Finally a quantity was gathered and sent to a merchant in Paris, where they were seen by Count de Douhet. The Count in 1867 presented a notice of them to the Academy of Sciences and pronounced them to be massive carbon, and a variety of the diamond. The exact localities in Brazil where it occurs we are unable to describe, but believe them to be situated in the Province of Bahia. As to the quantity gathered we are also unable to give a definite opinion, but have reason to think that it is quite limited; and, moreover, we have yet to learn that it occurs in any other diamond mines in the world.
The color of the carbon, or carbonado, as it is called by the Brazilians, is generally black, but it may be light-brown or of a greenish gray color, when diluted with clay. It is always opaque, but is not always compact, being sometimes quite porous, like pumice-stone. It never crystallizes, but generally appears in angular pieces in lumps or concretionary masses whose specific gravity is 3 to 3.4, while that of the transparent diamond is 3.5.
The black and perfectly crystallized diamond, which is very rare, is not to be confounded with this variety.
The hardness of the carbon is equal to that of the transparent diamond, and probably some of the purest and most compact specimens are harder even than the limpid variety; for the black gems are generally harder than the light-colored, and we have for instances the deep-blue sapphire, the black tourmaline, etc.
At first this newly discovered mineral was pulverized, and its powdered dust used to polish diamonds and other gems, and was then sold for a few francs the karat. Lately, however, science has applied its use to new inventions; and the demand for it in its application to the drill and the saw has increased its value to several dollars the karat, and the price is still increasing. Its advantages over the crystallized varieties are very decided, and it is as hard and has no cleavage planes, and is therefore far better able to resist the effects of shock.
The only diamond known to have been found in modern times in Western Europe is that picked up in a brook in the County of Fermanagh in Ireland. Its weight was not given, but it was stated to be of a reddish cast and valued by Mr. Rundell at twenty guineas. Some mineralogists have maintained that the stone in question was not in place and was probably brought in the crop of some bird of passage from Brazil or the tropical countries of America.
To us, however, a more plausible and probable theory would be that the stone was in place, and that its presence is no more remarkable than the gold nuggets found in the same country. In fact, this instance is no more strange than the finding of the great American diamond in Virginia, which was also a solitaire and many miles below the auriferous fields whence it is supposed to have drifted. We shall not be surprised to learn of the occurrence of diamonds in other parts of Europe. Pliny ends his chapter on the diamond by stating on the authority of Scepsius that diamonds are found in Germany and in the island of Basilia along with amber.
Eastern Russia was long ago suspected of being diamondiferous; and as early as 1826 Maurice Englehardt pointed out the resemblance of the Ural districts to those of Brazil. It was, however, left to Humboldt and his companions to make known the actual occurrence of these gems in this country. For in 1829, during their visit to Siberia, they discovered several diamonds on the estates of Count Porlier, about one hundred and sixty miles west of Perm, on the western declivity of the Ural Mountains. Active search having been instituted, forty diamonds were found in the detritus on the banks of the Adolfskoi. Strange to relate, they were discovered in the gold-bearing alluvium twenty feet above the stratum containing bones of mammoths and rhinoceroses. Since this period they have also been found at several other places along the Uralian chain.
In commenting upon the occurrence of these diamonds of the Adolfskoi which are preserved in the collection of Prince Butera, some of our best geologists have come to a startling conclusion.
Humboldt, Sir Roderick Murchison, and M. Verneuil, obtaining information from different points in Siberia, have been led to the belief that the diamond in these localities was formed at a date subsequent to the destruction of the mammoths.
Since this period Colonel Helmersen has made known other points along the Uralian chain of mountains where the gem has been found, as Ekaterinsburg, Kushvinsk, and Versch-Urak. But we have no information of “placers” of any considerable extent having been discovered, or the finding of the gem in sufficient numbers to warrant systematic explorations.
Future research may reveal other localities in Siberia where this gem occurs, for the country was known to the ancients as furnishing the adamas.
Amnian in the fourth century mentions the region of Agathyrsi as one of the gem-bearing countries; and this country included the Ural Mountains and part of Siberia. It is not at all strange that the exact localities should have been forgotten during the long intervening space of time and the many political convulsions that have interrupted commercial intercourse with those far-off regions.
It was well known that Scythia furnished the ancients with gold for centuries; but in modern times all trace of the localities was lost until revealed by the researches of German miners exploring for copper and iron. Stranger still, the locality of the gold mines in Spain, so famous in ancient times, is unknown at the present day.
The gold fields of the Southern States of North America have been known to be diamond-bearing for forty years or more, but as yet no earnest or well-directed search has been made for the gems. During this period of time more than thirty diamonds have been picked up by accident along the gold belt which extends from the central and eastern portion of Alabama, through Georgia, North and South Carolina, even to the interior of Virginia. All along this auriferous formation the itacolumite appears in the gravel beds or in ledges or even in large mountains in some localities.
In Alabama, where the itacolumite is abundant, several fine diamonds of three or four karats weight have been found.
The northeastern portion of Georgia has also yielded some beautiful stones to the miners while washing for gold. Some of these we have seen and found them to be of the purest water. The Glade mines, a few miles north of Gainesville, have yielded several fine diamonds, some of which have been cut in London. They were found by accident in the riffles of the gold-washing machines, and were preserved by the miners simply as curiosities. At the Horshaw gold mines, a few miles farther to the northeast, a large diamond was picked up, but unfortunately destroyed by the ignorance of the laborers, who unluckily reasoned like the ancients concerning its destructibility, and therefore tried the effects of a heavy sledge upon it while placed on an anvil. An examination of this last deposit in 1866 convinced the writer that it was a true diamond field; and search was rewarded with the finding of two small but well-crystallized diamonds. So far as we can ascertain, all the diamonds thus far discovered in these regions have been finely crystallized.
North Carolina has also yielded some fine specimens of three and four karats weight; but the largest diamond thus far found in the United States and preserved was picked up in 1856 on the banks of the James River, opposite the city of Richmond in Virginia. The spring floods had probably washed it down from the gold fields which are situated a few miles above. The stone was a well-defined octahedral crystal. Its weight, while in the rough state, was about twenty-five karats, and its color was of a faint greenish white tinge. Its transparency was perfect, but its refractions were somewhat impaired by a flaw or a speck in the interior.
The American diamond-cutting establishment of Morse, Crosby, & Foss, of Boston, cut this gem very successfully at the cost of about $1,300. The stone was purchased by a distinguished American athlete in New York, and worn by him in a breast-pin for many years.
None of these diamond fields have been examined systematically by experienced miners with a view to their development, and in fact no definite idea of their limit or their value can be given. But we have the impression that they are far more extensive than has been imagined by mineralogists. The returning gem-seekers who have been educated in the diamond mines of South Africa may investigate ere long these unknown districts and settle the question beyond further inquiry. In California, a few diamonds are reported to have been found here and there among the gold fields, but nothing like a gem placer has yet been revealed. The geological formations of Arizona and New Mexico are more promising than any part of the United States, and explorations may disclose extensive and valuable gem deposits in those regions. The originators of the famous diamond swindle in Arizona chose their locality with more than ordinary sagacity.
The account of this daring scheme reads more like romance than reality, and it was more than ordinary boldness that prompted the perpetrators to visit foreign lands, purchase quantities of rough diamonds and then plant them in a distant, desolate, and hostile country to entrap the wary speculator. The success of this piracy was fortunately checked by the sagacity of one of the United States geologists exploring the adjacent territory, who quickly disclosed the fraud, but not in time to prevent the swindlers from pocketing large sums of money from speculators in California.
Pliny mentioned Arabia as one of the localities of the gem; but modern investigators believe that he founded his views on the facts of the diamonds being obtained from Arabian merchants, and that they really came from other countries.
This probably is the true version of the commerce of the Arabians in those days; but we see no objection to the belief that Arabia may have been a diamond-bearing country in early times, and may possess undeveloped fields at the present day. Northern Africa was also asserted to be diamond yielding, and modern investigators have established the truth of the assertion.
In the year 1867 the attention of gem-seekers was turned to vague reports of the discovery of rich diamond fields in South Africa, and the pages of history were examined closely to prove that in ancient times this continent was known as a diamond country. It is undoubtedly true that Africa yielded diamonds to the ancients, for within thirty years several have been found in Algiers, and are now preserved in the collections of Paris. They were discovered in the auriferous sands of the river Goumal, in the Province of Constantine, by natives while washing for gold. They were small in size but of unmistakable character. This discovery strengthens the ancient report of the Carthaginians’ procuring the gems from the Etrurians, who brought them from the interior of Africa.
In 1867 a diamond was discovered by accident in the soil several hundred miles north of the Cape of Good Hope. The report was not credited, and it was not until a number had been found and tested that the attention of adventurous men was fairly aroused. Success soon rewarded the labors of the first bands of gem-seekers; and the news, widespread over the world, soon brought thousands of determined and hardy men, who are even yet earnestly exploring the gem districts and also revolutionizing the country.
The gem mines now under process of exploration are situated on the Vaal River and its tributaries, the best of them being found near the junction of the Vaal and Orange Rivers and from five to six hundred miles north of the Cape. The locality known as Du Toits Pan soon became famous and yielded a great number of diamonds, some of them over 100 karats and one reaching the great weight of 288³⁄₄ karats. The topography of the country around these mines is characterized by low, flat-topped hills, which strike the observer at once by their singularity. The storm clouds, their frequency, their dull gray hue, their constant commotion, and the nearness of their approach to the earth are also quickly noticed by the new-comer, so strangely different are they from the ordinary atmospheric changes.
Five miles to the north of Du Toits occurs one of the most remarkable mines yet discovered in any part of the world. It is called Colesberg Kopje, and although one of the richest spots of the globe, it is also one of the meanest places on God’s earth. Several thousand men have been actively engaged upon it for a number of years past, and many thousand diamonds have been taken from it. So rich has been its yield that it is stated that four thousand have been obtained in a single day.
The extent of the excavation is enormous, and yet all has been done by simple and even rude means. But little advantage has been taken of the use of machinery and skilled labor, and most of the operations have been conducted in a primitive manner. The distance to the coast and the great expense of transportation is perhaps the principal reason why different and more satisfactory arrangements have not been made.
The photographs of the appearance of this field and its excavations strike one with amazement. The countless array of tents in the distance on the borders of the deposit; the thousands of busy miners; the huge and deep ditches stretching across the plain, vast enough to float a fleet of men-of-war; the lofty mounds of thrown-up earth,—all together present a startling picture never to be forgotten.
The depths of these enormous ditches vary from ten to more than one hundred feet.
All this herculean labor has been performed in less than twenty years under the stimulus of extraordinary prosperity, and it indicates a determination to explore the country thoroughly.
As yet there has been no complete survey of these regions, and the extent of the diamond fields is still unknown. Sufficient evidence, however, has been received to indicate that they cover an area of one thousand square miles, and are situated principally in the Orange River Free State, but also extend into the Transvaal Republic and Cape Colony. These districts alone will afford remunerative labor for some time to come, and we have little doubt but that other fields of even greater extent will before long be discovered in other parts of Africa.
For a long time past we have been led to regard this continent as containing the most extensive and richest diamond deposits on the globe. A great portion of Africa belongs to the geological conditions which produce the diamonds, and the present explorations will educate a host of gem-seekers, who will not only investigate other parts of Africa, but will also explore other countries. Therefore we may expect the diamond trade to receive a strong impetus for some years to come, and that new mines may for a time reduce the present prices of the gem.
The largest diamond yet afforded by the South Africa mines is that called the Stewart. It was found at Waldeck’s plant, in November, 1872, by a man named Antonies. Its form was that of a modified octahedron, beautifully crystallized, and exhibiting a faint tinge of yellow. On the outside of the crystal were a few specks and flaws, but the interior appears to be free from imperfections. Its original weight was 288³⁄₈ karats.
A vast number of the diamonds found in these fields are tinged with a faint hue, generally yellow or faint brown. This peculiarity was also noticed with the yield of the Brazilian mines.
It is quite impossible to give a correct account of the quantity afforded by these mines up to the present time. It amounts to many millions of dollars, and is sufficiently large to produce a marked effect upon the market, but nothing like the panic which followed the discovery of the Brazilian mines. The value of the diamonds exported at Cape Town in 1871 is said to have been $7,500,000, but it was probably much greater.
Australia has afforded to the gold miners quite a number of small diamond crystals, and gem fields undoubtedly occur within its borders. Among the auriferous sands of the Maguarie River minute crystals have been picked by the careless miner from time to time, and other localities have also afforded specimens of the mineral, but no systematic search has yet been made for them. A number of these specimens of diamonds, although of minute form, were exhibited at Melbourne in 1865.
The islands of Java and Sumatra yield diamonds among their mineral treasures, but, strange to say, the island of Ceylon, which is the most remarkable gem deposit in the world, does not produce a single specimen. The island is not far distant from the gem districts of lower Bengal. The formation appears to be of the same character, but it is evident that the geological conditions which deposited the sapphire, the zircon, spinel, etc., differed from those required by the diamond.