DIAMOND: OCCURRENCE AND DISTRIBUTION 139 



having been found in the eastern States of Georgia, North Carolina, South Carolina, 

 Kentucky, Virginia, Wisconsin, and in the western States of California and Oregon. 

 Reported occurrences in other parts of the American continent, namely Sierra .Madre 

 in Mexico, and the gold mines of Antioquia in Colombia, South America, require 

 confirmation. 



The continent of Africa is, at the present time, by far the most important source of 

 diamonds, which have been collected here since the late sixties in ever increasing numbers, 

 far surpassing the yield from any other region. The exact locality of the deposits is on the 

 Vaal River, and in the neighbourhood of the town of Kimberley, both these localities being 

 in the division of Griqualand West, in the north of Cape Colony ; also in the adjoining 

 Orange River Colony, which, however, is of far less importance. Compared with the yield 

 of the African fields, all others are insignificant, although in comparatively recent times the 

 markets of the world were supplied from the sources which are now of such minor 

 importance. At the present day the diamond fields of the. Cape are the source of 90 per 

 cent, of the stones which come into the market. The reported occurrence of diamonds in 

 the auriferous sands of the river Gumel, in the province of Constantino, in Algeria, is 

 unauthenticatcd ; three stones were said to have been found here in 1833, but nothing more 

 bas been heard of this reputed discovery. The statement of Dr. Cunv, an African travellei', 

 that in the fifties a whole camel-load of diamonds was brought from Western Africa to 

 Darfur seems rather incredible. 



In Europe, diamonds have been found in Russia, in the Urals in the east, and in 

 Lapland in the west ; the stones are, however, met with only in small numbers, and their 

 importance lies in their mineralogical rarity. The repo)-ted occurrence of a few small 

 diamonds in Spain has some degree of probability ; but the supposed discovery of diamonds 

 in a stream in Fermanagh, Ireland, needs authentication. A reputed discovery in Bohemia 

 is certainly false ; in 1869 a single small diamond was noticed in a parcel of garnets at some 

 cutting works at Dlaschkowitz ; the matter was thoroughly investigated by V. von 

 Zepharovich, who proved beyond doubt that the diamond must have been introduced into 

 the parcel at the works, where such stones are used for boring garnets. 



Diamonds have been found in recent times in Australia, especially in New South 

 Wales, not altogether in inconsiderable numbers ; and Australian stones are. at least 

 mentioned in the markets. 



Finally we must record the interesting fact that diamond is not only a constituent of 

 the earth's crust, but also of extra-terrestrial bodies, the presence of small stones having 

 been in recent years proved in several meteorites. 



With regard to the mode of occurrence of diamonds, it is to be noted that in the 

 majority of localities they are found in secondary deposits, such as sands and gravels. 

 These masses of debris produced by the weathering of the original mother-rock of the 

 diamond are usually entirely loose and incoherent ; occasionally, however, as in Brazil and 

 India, they are converted by some cementing materials into firm conglomerates, breccias 

 and sandstones. In Brazil these rock masses, like the loose sa.nds and gravels at other places, 

 lie on the surface, and must therefore be reckoned among the most recent deposits of the 

 earth's crust. In India, and to a certain extent also in Brazil and North America, the 

 diamantiferous fragmentary rocks belong to earlier geological periods, being interbedded 

 with some of the oldest rocks, and thus representing the sands and gravels of veiy 

 remote ages. When these older fragmentary rocks come to the surface, they are 

 themselves in course of time attacked by weathering agents and supply material for new 

 secondary deposits, fi'om which diamonds are won by the ordinary process of washing. 



