Agate

Hebrew: "shebo" (shebuw) (Ex. 28:19), also "kadkod" (Ezek 27:16), and "chalkedon" (Rev 21:19, NRSV)

The word "agate" is used three times in the King James Bible and NRSV, and twice in the NKJV and NIV.

An agate was a precious stone in the breast-plate of the high priest (Ex. 28:19; 39:12), the second in the third row

This may be what we know as the agate today, a semi-transparent crystallized quartz, probably brought from Sheba, hence its name (compare to the Hebrew word "shebo").

The word "agate" is from the Greek name of a stone found in the river Achates in Sicily.

In Isa. 54:12 and Ezek. 27:16, the word "agates" is the KJV translation of the Hebrew "cadcod," which means "sparkling gem." Other translations, including the NKJV say "rubies," not "agates."