The headword, not registered in LSJ s.v., is presumably the plural of Latin album. (Note, however, that in Lewis & Short alba meaning a pearl is feminine singular; so in ch.21 of the fictional Life of the Emperor Heliogabalus (Elagabalus) in the Scriptores Historiae Augustae, by "Aelius Lampridius".)
[1] Or, perhaps less probably, pearl-oysters. See LSJ s.v. for these twin meanings. For 'pearls' cf. under epsilon 1419.