Beryls, it is thought, are of the same[3037] nature as the smaragdus, or at least closely analogous. India[3038] produces them, and they are rarely to be found elsewhere. The lapidaries cut all beryls of an hexagonal[3039] form; because the colour, which is deadened by a dull uniformity of surface, is heightened by the reflection resulting from the angles. If they are cut in any other way, these stones have no brilliancy whatever. The most esteemed beryls are those which in colour resemble the pure green of the sea;[3040] the chrysoberyl[3041] being next in value, a stone of a somewhat paler colour, but approaching a golden tint. Closely allied to this last in its brilliancy, but of a more pallid colour, and thought by some to constitute a separate genus, is chrysoprasus.[3042] In the fourth rank are reckoned the hyacinthine beryls; and in the fifth, those known as “aëroides.”[3043] Next, we have the wax-coloured beryls, and, after them, the oleaginous beryls, so called from the resemblance of their colour to that of oil. Last of all, there are the stones which closely resemble crystal in appearance; mostly disfigured by spots and filaments, and of a poor, faint, colour as well; all of them so many imperfections in the stone. The people of India are marvellously fond of beryls of an elongated[3044] form, and say that these are the only precious stones they prefer wearing without the addition of gold: hence it is that, after piercing them, they string them upon the bristles of the elephant. It is generally agreed, however, that those stones should not be perforated which are of the finest quality; and in this case they only enclose the extremities of them in studs of gold. They prefer, too, cutting the beryls in a cylindrical form, instead of setting them as precious stones; an elongated shape being the one that is most highly esteemed. Some are of opinion that beryls are naturally angular,[3045] and that when pierced they become improved in colour; the white substance being thus removed that lies within, and their brilliancy heightened by the reflection of the gold in which they are set; or, at all events, their transparency being increased by this diminution in their thickness. In addition to the defects already[3046] mentioned, and which are pretty nearly the same as those to which the smaragdus is subject, beryls are affected with cloudy spots,[3047] like those on the finger-nails in appearance. In our own part of the world, it is thought that they are sometimes found in the countries that lie in the vicinity of Pontus.[3048] The people of India, by colouring crystal, have found a method of imitating various precious stones, beryls in particular. CHAP. 21. (6.)—OPALS: SEVEN VARIETIES OF THEM.