Extended Strong's Greek Lexicon (Abbott-Smith based)
dark blue
Usage: ὑακίνθινος, -η, -ον (ὑάκινθος), [in LXX for תַּחַשׁ, תְּכֵלֶת ;] of hyacinth, hyacinthine (see: ὑάκινθος), "doubtless meant to describe the blue smoke of a sulphurous flame" (Swete): Rev.9:17 (Hom., Eur., al.).† (AS)