The word “amber” is used three times in the King James Bible (KJV) (Ezek. 1:4, 27; 8:2). The original Hebrew word is “chashmal” or “khash-mal.” In Rev. 1:15 and 2:18, the KJV translates the same word as “fine brass.” It is uncertain what this word actually means, but the consensus seems to be that it was probably not referring to the fossil resin of a tree, but rather to a metal. Some say it was polished bronze or brass; others say an alloy of silver and gold.
The NIV translates it as “glowing metal” and “like bronze glowing in a furnace.” The NRSV says “like gleaming amber” and “like burnished bronze.”