What does apsyctos mean in Latin?

apsyctos, a noun, means “An unknown kind of precious stone”.

What is the genitive of apsyctos?

The genitive singular is apsyctī. apsyctos is feminine, second declension.

noun · femininesecond declension

apsyctos f (genitive apsyctī)

apsyctŏs, i, f., = ἄψυκτος (uncolled),

I. a precious stone unknown to us, Plin. 37, 10, 54, § 148.

Borrowed from Ancient Greek ἄψυκτος (ápsuktos).