King James Bible Dictionary

Properly a flower of a reddish blue or deep purple (hyacinth), and hence a precious stone of that colour (Revelation 21:20). It has been supposed to designate the same stone as the ligure (Heb. leshem) mentioned in Exodus 28:19 as the first stone of the third row in the high priest's breast-plate. In Revelation 9:17 the word is simply descriptive of colour.

A precious stone.
Revelation 9:17; Revelation 21:20

a precious stone, forming one of the foundations of the walls of the new Jerusalem. (Revelation 21:20) Called hyacinth in the Revised Version. This is simply a different English rendering of the same Greek original. It is probably identical with the lighure of (Exodus 28:19) The Jacinth or hyacinth is a red variety of zircon, which is found in square prisms of a white, gray, red, reddish-brown, yellow or pale-green color. The expression in (Revelation 9:17) "of jacinth," is descriptive simply of a dark-purple color.

JA'CINTH, noun [a different orthography of Hyacinth.]

1. A genus of plants. [See Hyacinth.]

2. A species of pellucid gems. [See Hyacinth.] Revelation 21:20.