Emerald - Vine's Expository Dictionary of New Testament Words
Emerald[ A-1,Noun,G4665, smaragdos ]
is a transparent stone of a light green color, occupying the first place in the second row on the high priest's breastplate, Exodus 28:18. Tyre imported it from Syria, Ezekiel 27:16. It is one of the foundations of the heavenly Jerusalem, Revelation 21:19. The name was applied to other stones of a similar character, such as the carbuncle.
[ B-1,Adjective,G4664, smaragdinos ]
emerald in character," descriptive of the rainbow round about the throne in Revelation 4:3, is used in the papyri to denote emerald green.