amethyst, a gem in the third row on the ephod, breastplate of judgment worn by the high priest. Transliteration of the Septuagint word. Identification is not certain but is a purple stone perhaps a corundum or red or brown jasper.
STRONG'S WORD STUDY
H306 — אַחְלָ֑מָה
ach.la.mah · amethyst · Hebrew/Aramaic