9 
130 Transactions of the Royal Society of South Africa. 
a diamond sufficient at times to cause breakage under robust treatment. 
Many of the broken diamonds in the De Beers production may have fallen 
to pieces in the mining operations before they reached the sorting office. 
This is not an admission, of course, that they have been smashed by the 
machinery, for broken diamonds are found in the matrix : the hypothesis is 
that they are ready to break up, and that tlie mining operations, by shaking 
them up, help them to do so right out. 
Fundamentally there is no difference between the spontaneous bi'eaking 
of a pure coloui-less crystal diamond containing an inclusion and that of 
opaque or clouded diamond. In the former case there is a relatively large 
force concentrated at one place, and causing a delinite split there ; in the 
latter the distributed particles and finely divided colouring matter set up 
many small strains which, acting together, cause disruption of a similar sort 
to the pulverisation of the blue ground when this is exposed to the air. 
The terms " bursting " and "exploding," therefore, must be regarded as 
Bultfontein made, x 5^. 
exaggerations of a simple tumbling to pieces. Opaque diamond will often 
break up quite easily. Wesselton black bort, when on the sorting tables, is 
mostly in fragments, or otherwise so much cracked as to be easily broken. 
From outside appearance there is more indication of bursting (as the term 
has been defined above) in a colourless diamond containing an inclusion 
than there is in any clouded stone. But no early digger has ever suggested 
the extension of the scope of the 40th Article so as to comprise the former. 
4. Pseudo-Cleavage. 
Some of the cleavages found in the Wesselton and Bultfontein mines 
appear at first sight to be fragments of broken diamonds. Closer inspection, 
however, shows that many have not the sort of freshly fractured surface 
that is got when a diamond is deliberately broken, but seem to have under- 
gone some natural process of growth and solution subsequent to their 
disruption. And many, as said before, seem to have crystallised in a tight 
corner, where they had no chance to grow symmetrically. An inkling of 
what may some'^imes take place is given by a Bultfontein diamond in my 
collection. This specimen is a clouded brown made of the orthodox spinel 
