232 PRECIOUS STONES.
cymophane identical in all respects with the cymo-phane found in America, in small but very perfectly formed crystals.
processes we have just described are all distinguished by special
features, though depending, as already mentioned, on a small number of
laws. It is probable that nature has employed them by turns. In any
case they suffice to explain the formation of the greater number of
crystallized mineral substances at present known.