Abbott-Smith Manual Greek Lexicon
ὑακίνθος (G5192)
1 ὑακίνθος , -ου, ό [in LXX chiefly for תְּכֵלֶת ;] hyacinth ; in cl., a flower, prob. the dark blue iris; in late writers, a precious stone of the same colour, perhaps the sapphire: Re 21:20 (Phil., FlJ, al.).†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain