In Ancient Greek mythology, the Sun God Apollo was usually assigned the lyre. Apollo represented an ideal type of manliness, and was associated with music, poetry, and prophesy. The feminine Latin name Apollonia, which is the Latin feminine form of the Greek masculine name "Apollonios," of the same root as the name of the sun god "Apollo." Versions of this name became extremely popular during the Middle Ages.
Now your cameo subject is a female, so either Apollonia (feminine of Apollo) or Muse (as there is no Goddess associated with the lyre) and associated with the stringed musical instrument (shoulder, on cameo at approx. 9 pm) of ancient Greece and elsewhere, called a Cithara which is similar to the lyre and played with a plectrum. Terpsichore, the muse of dance, would carry a lyre. So did Erato, the muse of lyric poetry, although her instrument was a Cithara, an instrument related to the lyre.
