("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.

[Footnote 5: "Lover's Complaint", l. 37.]

[Footnote 6: "Idem", l. 286.]

[Footnote 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.

There can be no doubt that Shakespeare must have seen many fine
jewels and glittering gems in pageants and processions during his
residence in London. On certain special occasions the players were
summoned to assist at royal functions, provision being made by the
royal treasury for rich materials to be used in making special
doublets and mantles for wear on these occasions. It has been
suggested that the rich jewelling of many of the court portraits by
Holbein and others must have impressed the poet by their wealth of
color spread before his eyes; but it is nowise sure that he ever had