Ampyx, (a kind of jewelry) called by the Romans
frontale, was a broad band or plate of metal, which Greek ladies of rank wore upon the forehead as part of the head-dress (
Iliad Book 22.468 to 470; Aeschyl. Supp. 431; Theocr. i.33). Hence it is attributed to the female divinities. Artemis wears a frontal of gold
hryseian ampyka, Eurip. Hec. 464); and the epithet
hrysampykes is applied by Homer, Hesiod, and Pindar to the Muses, the Hours (Horae), and the Fates (Moirae). From the expression
kuanampuyka in a fragment of Pindar, we may infer that this ornament was sometimes made of blue steel instead of gold; and the Scholiast on the above cited passage of Euripides asserts, that it was sometimes enriched with precious stones. The frontal of a horse was called by the same name, and was occasionally made of similar rich materials. Hence, in the Iliad, the horses which draw the chariots of Hera and of Ares are called
hrysampykes. ...Frontals were also worn by elephants (Liv. xxxviii.40). Hesychius supposes the men to have worn frontals in Lydia. They appear to have been worn by the Jews and other nations of the East (Deut. vi.8, xi.1
cool .
-William Smith