What stone represents the tribe of Reuven on the breastplate of the high priest?

Answer 1

There are a number of authorities who assert differing methods by which the breastplate included the names of the 12 tribes. According to Talmud Yoma 72 and Rabbeinu Bachya: because the breatsplate was used as a tool to derived certain prophetic messages, all of the letters of the Hebrew alphabet needed to be present -- but the names of the 12 tribes are missing 3 letters: chet, tet and tzadi. To include these letters on the breastplate stones, the names of Avraham, Yitzchak and Yaakov and the words "Shivtei Yeshurun" were also engraved. Then, each stone had 6 letters on it to indicate 6 days of Creation. If you add the letters of the Patriarchs and "Shivtei Yeshurun" to the letters of the 12 tribes, it will allow for 6 letters per stone. Reuvain was Odem, a red jewel. The segulah of wearing red stones to prevent miscarriages is in the merit of Reuvein giving his mother the duda'im flowers. According to other traditions, though, there were other ways that the tribes were written, and I believe one of them may have had the names of the tribed broken up, in which case there would not necessarily have been "a stone" for each tribe -- that's the purpose of this lengthy explanation. (Moshe Weissman, The Midrash Says, Shmos, p 284-6 Benei Yakov Publications 1980)