Job 28:19 Midrash

לֹֽא־יַ֭עַרְכֶנָּה פִּטְדַת־כּ֑וּשׁ בְּכֶ֥תֶם טָ֝ה֗וֹר לֹ֣א תְסֻלֶּֽה׃ (פ)

The topaz of Ethiopia shall not equal it, Neither shall it be valued with pure gold.

Read midrashic interpretation of Job 28:19: and classical rabbinic exegesis.