The Hoshen Mishpat, the breastplate of the Kohen Gadol (Jewish High Priest) from the days of Jerusalem's Holy Temple, contained twelve different precious stones: one for each tribe fo Israel. Especially in recent times, it has served as an increasingly popular template for Jewish jewelry and other decorative uses.
Judaica Webstore has a wonderful selection of Hoshen necklaces, earrings, and rings to suit any taste!