This word represents two Hebrew words. The first may he a general term to denote any bright,sparkling gem , (Isaiah 54:12) the second, (Exodus 28:17; 39:10; Ezekiel 28:13) is supposed to be and smaragdus or emerald.
Smith’s Bible Dictionary
Carbuncle
Smith’s Bible Dictionary, William Smith (1863). Public domain, from the CrossWire SWORD module.