''Richer'' - implies that the "onyx" is a sardonyx of gem quality, and perhaps that it's carved into a cameo.

''Richer'' - implies that the "onyx" is a sardonyx of gem quality, and perhaps that it's carved into a cameo.

(Onyx, and sardonyx, are not especially valuable, themselves, but they can be very valuable when carved.  They are workable minerals, and the bands of different colors make them popular for bas-relief cameos.  Many sardonyx cameos have survived from Roman times, and from Elizabethan times as well, some of them exquisitely carved.  This does not prove that the gem Claudius shows is carved, only that the use in making cameos is a reason that onyx, and sardonyx, have been well known since ancient times.  However, it is entirely possible Claudius is displaying a sardonyx cameo.  The Crown of Denmark has carved stones, not that Shakespeare had to know that, since carvings done in valuable materials are typical of royal jewelry.)

Onyx, and sardonyx, are not especially valuable, themselves, but they can be very valuable when carved.  They are workable minerals, and the bands of different colors make them popular for bas-relief cameos.  Many sardonyx cameos have survived from Roman times, and from Elizabethan times as well, some of them exquisitely carved.  This does not prove that the gem Claudius shows is carved, only that the use in making cameos is a reason that onyx, and sardonyx, have been well known since ancient times.  However, it is entirely possible Claudius is displaying a sardonyx cameo.  The Crown of Denmark has carved stones, not that Shakespeare had to know that, since carvings done in valuable materials are typical of royal jewelry, and fancy jewelry in general.