Heb. nophek (Ex. 28:18; 39:11); i.e., the “glowing stone”, probably the carbuncle, a precious stone in the breastplate of the high priest. It is mentioned (Rev. 21:19) as one of the foundations of the New Jerusalem. The name given to this stone in the New Testament Greek is smaragdos, which means “live coal.”

a precious stone of a rich green color, upon which its value chiefly depends. This gem was the first in the second row on the breastplate of the high priest. (Exodus 28:18; 39:11) It was imported to Tyre from Syria, (Ezekiel 27:16) was used as a seal or signet, Ecclus. 32:6, as an ornament of clothing and bedding, (Ezekiel 28:13; Judges 10:21) and is spoken of as one of the foundations of Jerusalem. (Revelation 21:19) Tob. 13:16. The rainbow around the throne is compared to emerald in (Revelation 4:3)