Extended Strong's Greek Lexicon (Abbott-Smith based)
hyacinth
Usage: ὑακίνθος, -ου, ό [in LXX chiefly for תְּכֵלֶת ;] hyacinth; __(a) in cl., a flower, prob. the dark blue iris; __(b) in late writers, a precious stone of the same colour, perhaps the sapphire: Rev.21:20 (Phil., FlJ, al.).† (AS)