HYACINTH
(gr. “hyakinthos”).
In the Bible it denotes a precious stone of an intensely purple color.
In Rev. 9:17 the horsemen have breastplates of fire, hyacinth (cf. RVR 77) and sulfur.
The hyacinth constitutes the eleventh foundation of the heavenly Jerusalem (Rev. 21:20).
It also appears in several passages of the OT in the LXX, in Ex. 28:19; 39:12, forming part of the third row of the high priest’s breastplate. In Esther 1:6, in a luxurious display of the monarch of Persia.