NOTES ON DIAMONDS 



FKOM 



THE O^^PE OF GJ^OOD HOFEJ 



By Professor TENNANT, F.R.G.S., 



Mineralogist to Her Majesty ^ 149, Strand, London, W.O. 



The first South African diamond was found in Marcb, 1867.2 Qn examining 

 its X->hysical characters, it was pronounced by Dr. Atherstone to be genuine. 

 When this stone was received in London, it created considerable interest, and 

 also some degree of suspicion, some persons having asserted that it was brought 

 forward for mercenary purposes; letters even appeared in the public papers 

 implying that it was impossible it could have been found near Hope Town. As 

 Dr. W. G. Atherstone, P.G.S., of Graham's Town (who in March, 1867, examined 

 and pronounced the stone to be a diamond), is now in Bristol, I beg to offer a few 

 general remarks on the Gape diamonds, and also to express in public my thanks 

 to him. 



The late Mr. Mawe, who wrote on diamonds, and described their mode of 

 occurrence in his Travels in Brazil (London, 1812), often expressed to me his 

 opinion of the probability of their existence in South Africa, and said that if 

 people only knew them in the natural state he felt confident they would be 

 found.^ He died in 1829, and I took every opportunity to make the subject 

 known by means of short papers, accompanied by figures showing the ordinary 

 crystalline form of the diamond.* 



The number and quality of diamonds from the Cape are equal to those from 

 the Brazils, which have chiefly supplied Europe during the last eighty years. 



About ten per cent, of the Cape diamonds may be classified as of the first 

 quality, fifteen per cent, of the second, twenty per cent, of the third ; the 

 remainder, under the name of hort, are employed for cutting diamonds, and for 

 the various economic purposes to which this valuable substance is applied by the 

 glazier, the engineer for drilling rocks, the lapidary, and others. Many diamonds 

 contain specks and cavities ; these are placed in the hands of skilled workmen who 

 are acquainted with the cleavage, and by careful manipulation they are frequently 

 able to remove these blemishes, and so to obtain portions of the gems of the first 

 quality for making small " brilliants," " roses," and " tables." 



Two hundred years ago the art of cutting and polishing of diamonds was 

 carried on in London with great success ; after which it was transferred chiefly 

 to Holland ; but several attempts have been made to re-establish the trade in this 

 country. 



In 1874 the Turners' Company offered prizes, in the form of medals and the 

 freedom of the City of London, for the best specimens of diamond-cutting. The 



^ Read befoi-e the Geological Section of the British Association at Bristol, September 1st, 

 1875. 



2 Proceedings of the Royal Geographical Society, 1868. 



' Professor Tennant explained that the diamond in its natural state bore considerable 

 resemblance to a piece of gum. 



* See a letter to the Editor of the "Illustrated London News" for January 31, 1852, 

 and Lecture XV. on " Gems and Precious Stones," delivered before the Society of Arts, March 

 24th, 1852, at the suggestion of H.R.H. Prince Albert, on the results of the Exhibition. 



