Kimherley Diamonds : Especially Cleavage Diamonds. 
73 
upon memory. While the expert may honestly think that the diamonds 
now mined are brighter, or less bright, than they used to be, there is just 
the possibility that his eyes may have deteriorated or his memory been at 
fault. Moreover, it is not practicable in the process of mining to keep the 
diamonds belonging to different columns of the same pipe entirely separate, 
and also the columns may not be of the same relative cross-section 
throughout, so that at one level in the mine the output may consist of a 
greater proportion of diamonds from one column than it does at another 
level. 
4. OCTAHEDRA. 
The perfect octahedron is a rarity. Perhaps a few dozen have been 
found in the mines of the Kimberley group in forty years, and one at any 
rate of these was found entirely enclosed in another diamond — which suggests 
the possibility that any .octahedron of a perfect shape, with sharp edges that 
is, may have spent its existence, until it reached the surface, inside another 
diamond. Bauer's statement that " the edges and corners of the crystals 
[of Kimberley diamonds] are always perfectly sharp, not even the faintest 
trace of rounding can be detected," is not even approximately true. 
Yellow octahedra are rare. The common bright yellow diamond is nearly 
always rounded. 
5. Colours. 
Orange-coloured diamonds are only found, as a rule, in the Wesseiton 
Mine. This is curious, too, for a priori one would have expected to find them 
in mines where yellow diamonds abound, i. e. in De Beers, Kimberley or 
Dutoitspan. They are practically always in misshapen fragments, like their 
associated minerals garnet and zircon, and doubtless owe their condition to 
much the same causes as wore or broke down those. They are nearly always 
small, not often exceeding 1 carat, and not more than half a dozen or so of 
them are found in a month. They keep their original colour pretty well, 
as a rule, after cutting. In the collection of brilliants exhibited in the 
Kimberley office of the De Beers Company is a beautiful rich orange-coloured 
diamond weighing 2 carats, cut from one of the largest of such fragments 
yet found. G. H. Smith's assertion (' G-em Stones,' p. 151, 1912), that the 
" Wesseiton Mine yields a large proportion of flawless octahedra, but above 
all a large number of beautiful deep-orange diamonds " is perhaps approxi- 
mately true as to the first half, but not reasonably true as to the second. 
Pale lilac fragments are met with at rare intervals, and one reddish lilac 
diamond has been found and preserved, which, in shape, is like a long, flat 
bean, and yet has natural, though possibly secondary, faces. 
Now and then stones with a greenish cast are found, chiefly in De Beers 
and Kimberley. They range in colour from a faint chrysolite green to sage. 
