170 Brs. F. H, Hatch and G. S. Corstorp/iiue— 



V. — A Desckiption of the Big Diamond recently found in the?. 

 Premier Mine, Transvaal. 



By F. H. Hatch, Ph.D., F.G.S., and G. S. Corstorphine, Ph.D., F.G.S. 



(PLATES VII AXD VIII.) 



GEE AT interest has been excited, not only in the Transvaal, but 

 throughout the world, by the discovery at the Premier Mine, 

 on Wednesday, the 25th January, 1905, of the largest diamond 

 hitherto known. The stone was found by Mr. Wells, Surface 

 Manager, in the yellow ground about 18 feet from the surface, 

 a brilliant flash of light from a projecting corner having caught his 

 attention. After a preliminary cleaning it weighs 3,024^ carats. 

 According to Gardner Williams the South African carat is equivalent 

 to 3-174: grains; consequently the diamond weighs 9600'5 grains 

 troy or 1-37 lbs. avoirdupois. Through the courtesy of the Directors 

 of the Company, we have been enabled to make an examination of 

 the stone, with the following result : — Roughly speaking, it measures 

 •4 by 2J by 2 inches ; but its size and shape will be best realized hy 



Diagrammatic Projection (to half scale). 



reference to the photographs reproduced on Plates VII and VIII, 

 which represent the diamond from four different points of view 

 and its actual size. These beautiful photographs were taken by 

 Mr. E. H. V. Melvill for the purposes of this description. The stone 

 is bounded by eight surfaces, four of which are faces of the original 

 crystal, and will be referred to in this description under the letters 

 A, B, C, D, and four are cleavage surfaces, the cleavage being of 

 course parallel to the face of the octahedron. In the following 

 description these cleavage surfaces are referred to under the letters 

 E, F, G, H. They are distinguished from the original octahedral 

 faces by greater regularity and smoothness. The shape and relative 

 position of these various surfaces can be seen in the diagrammatic 



