Kimherley Diamonds : Esjoecially Cleavage Diamonds. 
83 
possible case of spontaneous breakage is known in the De Beers' sorting- 
office, and another, in which a crack was found in a diamond where no crack 
was observed — and the chances are, did not exist — before. Besides this, 
there are many brown and other fragments which do possess very fresh - 
looking cleavage faces, and so might have done as the frog did in the fable. 
And then there is the deduction from the statistics, previously remarked 
upon, that the proportion of brown cleavages to brown stones is unduly 
high. All this hints at the possibility of some measure of early or late 
spontaneous disintegration, but no more. Moreover, a great many broken 
diamonds are not brown or smoky at all. Anyway, diamonds do not explode 
of themselves under meteorological conditions. It is said that certain 
philosophers, acting under the orders of the G-rand Duke of Tuscany, once 
caused a diamond to explode by exposing it to the sun's rays in the focus of 
a powerful lens two-thirds of a Florentine ell in diameter ; but in this case, 
since the diamond was of a good size — nearly ten carats in weight — the 
result might have been caused by unequal heating rather than by the terrific 
heat alone. 
If heat will not cause a diamond to shiver (!) according to Crookes, and 
moisture will prevent such a catastrophe according to Williams,* it is not 
easy to understand what any " cunning dealer," wishing to buy but taking 
no unnecessary risks, has to gain by encouraging sellers to handle their 
goods freely or carry them in their warm pockets, which is what we are told 
the cunning dealers do ; and cunning indeed they must be if they can so 
contrive, and foolish the seller who could be so circumvented. It is to be 
suspected that much of the myth that has collected round the nucleus of 
an occasional accident to a smoky diamond is derived from the old story 
of Albertus Magnus, that a diamond immersed in the fresh, warm blood of 
a goat (especially if the animal had previously browsed on parsley or drunk 
wine) would burst. Pliny, it will be remembered, had a similar idea — 
namely, that the blood of a billy-goat had power to lessen the molecular 
cohesion of the adamas stone, which stone seems to have been diamond but 
may have been something else : " The blood, however, must be no otherwise 
than fresh and warm ; the stone, too, must be well steeped in it, and then 
subjected to repeated blows ; and even then it is apt to break both anvils 
and hammers of iron if they be not of the finest temper" (xxxvii, 15). 
With reference to the hypothesis of heat causing a diamond to break or 
explode when it is brought to the surface, the highest temperature to which 
it would be subjected above ground would be experienced on the depositing 
floors under the sun's rays, say about 60° C. (140° F.). The temperatures 
underground at the greatest depths yet reached are not so high as this, 
* A few experiments have been made with the object of ascertaining whether a 
moderate heating (up to a temperature of 100° C. in water) will create strain in a 
diamond or vary a strain already there ; but with no proof as yet that it can. 
