This proves the poet's familiarity with the idea that gazing on an emerald benefited weak sight, an idea expressed as far back as 300 B.C. by Theophrastus, a pupil of Aristotle, and repeated by the Roman Pliny in 75 A.D. The "Lover's Complaint" furnishes another pretty line (198) contrasting the different beauties of rubies and pearls:
Of paled pearls and rubies red as blood.
In "Venus and Adonis", honey-tongued Shakespeare writes of a "ruby-colored portal".
Pearls are noted six times, usually as similes for tears, and tears are likened to "pearls in glass" ("Venus and Adonis", l. 980). A tender line is that in the "Passionate Pilgrim" (hardly from Shakespeare's hand, however):
Bright orient pearl, alack, too timely shaded.
More varied are the allusions to rock-crystal or crystal, as the poet calls it. In one place ("Venus and Adonis", l. 491) there are "crystal tears", and these form "a crystal tide" that flows down the cheeks and drops in the bosom (Idem, l. 957). On the other hand, the eyes are likened to this stone, as in "crystal eyne" ("Venus and Adonis", l. 633), or "crystal eyes" (Sonnet xlvi, l. 6). There are also "crystal favours", [5] a "crystal gate", [6] and "crystal walls", [7] the two characteristics of brilliancy and transparency suggesting these uses of the term.
[5] "Lover's Complaint", l. 37.
[6] "Idem", l. 286.
[7] "Lucrece", l. 1251.
The emeralds of Shakespeare's age had been brought from Peru by the Spaniards and had originally come from Colombian mines, such as those at Muzo, which are still worked in our day. The location of some of the early deposits here appears to have been lost sight of since the Spanish Conquest. The emeralds of Greek and Roman times, and of the Middle Ages, came from Mount Zabara (Gebel Zabara), near the Red Sea coast, east of Assuan, where traces of the old workings were found in 1817; these mines were reopened by order of Mehemet Ali, and were worked for a brief period by Mons. F. Cailliaud.