Dama Ben Netina and the Gems for the Ephod

(Exodus 25:7) "Onyx stones and stones for the settings." The school of Sheila taught: what is the reasoning of Rabbi Eliezer, who said that a red heifer is not bought from gentiles? Because it is written (Numbers 19:2), "Speak to the children of Israel" - the children of Israel, and not the gentiles, and so on. And should you say that this is indeed so, did not Rav Judah say in the name of Samuel: they asked Rabbi Eliezer the Great, how far does the honoring of father and mother extend? He said to them: go and see what a certain gentile did for his father in Ashkelon, and Dama ben Netina was his name. Once the sages sought from him stones for the ephod at a profit of six hundred thousand - and Rav Kahana taught it as eighty myriads of profit - and the key was lying beneath his father's pillow, and he would not disturb him. "Onyx stones" interrupted the matter [stands apart in the verse]. But surely "and stones for the settings" is written, for it then joins them back together. And further, the latter clause teaches: the next year a red heifer was born in his herd, and so on. Rabbi Eliezer holds two positions.