In all[1] gold ore there is some silver, in varying proportions; a tenth part in some instances, an eighth in others. In one mine, and that only, the one known as the mine of Albucrara, in Gallæcia,[2] the proportion of silver is but one thirty-sixth: hence it is that the ore of this mine is so much more valuable than that of others. Whenever the proportion of silver is one-fifth, the ore is known also by the name of "electrum;"[3] grains, too, of this metal are often found in the gold known as "canaliense."[4] An artificial[5] electrum, too, is made, by mixing silver with gold. If the proportion of silver exceeds one-fifth, the metal offers no resistance on the anvil.

Electrum, too, was highly esteemed in ancient times, as we learn from the testimony of Homer, who represents[6] the palace of Menelaüs as refulgent with gold and electrum, silver and ivory. At Lindos, in the island of Rhodes, there is a temple dedicated to Minerva, in which there is a goblet of electrum, consecrated by Helena: history states also that it was moulded after the proportions of her bosom. One peculiar advantage of electrum is, its superior brilliancy to silver by lamp-light. Native electrum has also the property of detecting poisons; for in such case, semicircles, resembling the rainbow in appearance, will form upon the surface of the goblet, and emit a crackling noise, like that of flame, thus giving a twofold indication of the presence of poison.[7]