Kimherley Diamonds : Esi^ecially Cleavage Diamonds. 
81 
which it is reflected inwards, so that if the stones were to be broken the 
fragments would assume a lighter tint. We have also to remember such 
a fact as that the deepest coloured glass appears lighter in colour when 
broken into small enough fragments, and quite white when reduced to 
powder. Diamonds may look lighter in colour because they are broken ; 
they do not break because they are lighter. 
9. Cleavages. 
One point to be noted concerning what are called cleavages is that some 
of them are not broken diamonds at all. Wodiska's statement (' A Book of 
Precious Stones,' 1910) that "cleavage" means broken stones is too uncom- 
promising. " Cleavage " is a trade term which indicates not only diamonds 
now broken, but those which will have to be broken before being finally cut 
into gems — potential cleavage, in fact. All very misshapen stones and 
interpenetrating crystals, besides broken pieces, are cleavages in the eyes of 
aKimberley diamond merchant, just as all flesh is grass, and so are feathers 
too, ill the eyes of tlie philosopher. Bultfontein produces numbers of these 
interpenetrating crystals, or cross-grained stones, as they are called. Some 
of them take strange forms : a fine white one in my collection is like two 
mace-heads, with sharp, projecting points, joined together. The term 
"cleavage" does not apply, however (as Bauer says it does), to crystals 
containing spots which would have to be cleaved before being cut. A 
crystal containing spots is a " spotted stone," and is denominateil dark, 
black, or black rejection, according to its quality. Some of these so-called 
cleavages have evidently crystallised in a tight corner, judging by their dis- 
torted outlines and by the fact that sporadic specimens appear to have 
surfaces of attachment like quartz. Others appear to have been broken at 
an early stage, and to have undergone further growth or suffered resorption. 
It is truly remarkable how many of these so-called cleavages seem to have 
been naturally refaced either with a nascent or with a pocky surface. The 
triangular indentations indicating growth — so common on the faces of 
Wesselton octahedra— do not, nevertheless, seem to occur on these naturally 
renovated cleavage faces ; instead, striations like those on yellow diamonds 
are the rule. 
10. Broken Diamonds. 
The origin of the numerous broken fragments of diamond is somewhat 
of a mystery. O. F. Williams (p. 492) remarks that — " Some observers 
claim that the broken diamonds which are extracted are broken during: the 
process of winniug them. It is admitted that diamonds may be broken in 
the process of mining and the subsequent operations of winning, but these 
cases are exceptional. Fragments of diamonds are very frequently found 
embedded in the blue ground, and there is no doubt in the mind of anyone 
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