Exodus 39:12 Midrash

וְהַטּ֖וּר הַשְּׁלִישִׁ֑י לֶ֥שֶׁם שְׁב֖וֹ וְאַחְלָֽמָה׃

And the third row, a jacinth, an agate, and an amethyst.

Read midrashic interpretation of Exodus 39:12: and classical rabbinic exegesis.