The emerald is said to be at enmity with all impurity; and will break if it do but touch the skin of an adulterer. We cannot forego Nicols’ description of this stone: “The emerald is a pretious stone or gemine of so excellent a viridity or spring-colour as that if a man shall look upon an emerald by a pleasant green meadow, it will be more amiable than the meadow, and overcome the meadow’s glorie by the glorie of that spring of viriditie which it hath in itself. The largeness of the meadow it will overcome with the amplitude of its glory, wherewith farre above its greatnesse it doth feed the eie; and the virescencie of the meadow it will overcome with the brightnesse of its glory, which in itself seemeth to embrace the glorious viridity of many springs.” It is reported of Nero that he was wont to behold the fencers and sword players through an emerald as by a _speculum_ or optic glass and that for this cause the jewel is called _gemina Neronis_. According to Pausanias,[181] the favorite ring of Polycrates, a tyrant of Samos, contained an emerald. He was advised by Amasis, king of Egypt, to chequer his continued prosperity and enjoyments by relinquishing some of his most favorite pleasures; and he complied by throwing into the sea this most beautiful of his jewels. The voluntary loss of so precious a ring affected him for some time; but a few days after, he received, as a present, a large fish, in whose belly the jewel was found.[182] Albertus Magnus observes: “If you would sharpen the understanding, increase riches and foresee the future, take an emerald. For prophesying, it must be placed beneath the tongue.” The topaz is said to free men from passions and sadness of mind; and that, if it be cast into boiling water, it will suddenly “astonish it into coldness.” The agate is stated to be good against poisons. It is reported of the eagle that it doth carry this gem into her nest to secure her young from the bitings of venomous creatures. “If,” says Albertus Magnus, “you would avoid all dangers and overcome all earthly things and possess a stout heart, take an agate. It causes danger and opposition to vanish and makes a man strong, agreeable and of good cheer.” The sapphire, according to St. Jerome, will procure the wearer the favor with princes and all others, pacify enemies, free him from enchantments, bonds and imprisonments and it looseth men out of prison and assuageth the wrath of God. It is reported of it that it is of so contrary a nature to poisons that if it be put into a glass with a spider or laid upon the mouth of the glass where it is, the spider will quickly die.[183] It is said to keep men pure and, therefore, is worn by priests.[184] The Gentiles consecrated this gem to Apollo, because, in their inquiries at his oracle, if they had the presence of this gem with them, they imagined they had their answer the sooner.