A.unconquerable:
I. Subst., adamant, i. e. the hardest metal, prob. steel, χλωρός, πολιός, Hes.Sc.231, Th.161: metaph., “ἀδάμαντος ἔχον κρατερόφρονα θυμόν” Op. 147; of anything fixed, unalterable, ἔπος ἐρέω ἀδάμαντι πελάσσας Orac. ap. Hdt.7.141; ἀδάμαντος δῆσεν ἅλοις fixed them with nails of adamant, i. e. inevitably, Pi.P. 4.71, cf. APl.4.167 (Antip. Sid.); “τὸν ἐν Ἅιδα κινήσαις ἀδάμαντα” Theoc.2.34.
2. diamond, Thphr.Lap.19, Paus.8.18.6, Peripl. M.Rubr.56; prob. so meant in Pl.Ti.59b, Plt.303e, cf. Plin.HN37.55.
II. Adj., unbreakable, “ἀνακτίτης” Orph.L.192.