Emerald

"Polycrates considered which of his treasures it would most grieve his soul to lose, and came to this conclusion: he wore a seal set in gold, an emerald, crafted by Theodorus son of Telecles of Samos."

"This gem of chastity, this emeraud."

"But for all that, Sancho, I have falne upon one thing, which is, that thou didst ill describe her beautie to me: for if I forget not, thou saydst she had eyes of Pearles, and such eyes are rather the eies of a Sea-Breame then a faire Dames: but as I thinke, Dulcineas eyes are like two greene Emeralds rared with two Celestiall Arkes, that serve them for Eyebrowes. And therefore for your pearles, take them from her eyes, and put them to her teeth: for doubtlesse, Sancho, thou mistook'st eyes for teeth."

"The deep green emerald, in whose fresh regard Weak sights their sickly radiance do amend."

"I took ship for Tyre in Phoenicia, where I had learned by inquiry that there was a holy temple of Heracles. There I saw it, richly equipped with many other offerings, besides two pillars, one of refined gold, one of emerald: a great pillar that shone at night."