50 NATURAL HISTORY OF PRECIOUS STONES, &c.
	a singular artifice could stick a Diamond upon the point of a needle ; and moreover, without the aid of any instru­ment or material, other than those furnished hy the human body, divide it into fine scales like a piece of talc : " a comparison which attests the truth of his boast. The arcanum, however, like many other valuable mediaeval recipes, died with the discoverer, until Dr. Wollaston again hit upon it, and made thereby some profitable specu­lations by purchasing large Diamonds at a low price which had been rejected by the jewellers on account of their bad shape and fulness of flaws, and skilfully sub­dividing them into smaller and perfect crystals. The learned chemist's discovery had, however, been long anti­cipated by the Indian lapidaries, like most other secrets in this branch of science. Tavernier accounts for the prevalence of " thin stones " (tables) at the Eaolconda mine, by the fact that the Diamonds got flawed from the miners breaking the rocks containing the veins of sand, their matrix, by violent blows of iron crows—" and when they see that the flawed stone is of good size, they set to work to diver, that is, to split it, at which they are much more expert than ourselves."—(ii. 327.) ' It will naturally be asked why the ancients should have ever desired to reduce to fragments so rare a possession : but Pliny supplies a sufficient motive : " When by good luck they succeed in breaking the stone, it flies into such small scales (crustas) that they are scarcely visible. These are in request with gem-engravers, and are mounted in iron tools,* there being no substance so hard that they