Definition of callais in US English:

callais

noun

Mineralogy Archaeology
  • A sea-green or turquoise precious stone, often identified as (a form of) turquoise, or (less commonly) variscite.

Origin

Late 16th century; earliest use found in Arthur Golding (d. 1606), translator. From classical Latin callais greenish-blue precious stone, turquoise (Pliny), probably from an unattested Greek form *καλλαίς; compare Hellenistic Greek καλλάϊνος (also καλάϊνος) greenish-blue.

Pronunciation

callais

/ˈkaleɪɪs/