The Work of Sapphire Stone ("Ma’aseh Livnat Ha-Sapir") is a mystical-philosophical treatise of German-Jewish thinker Salomon Maimon (1753-1800). Published for the first time, the work presents Maimon's only foray into the realm of Jewish mysticism, uniquely documenting the delicate interplay in his thought between speculative Kabbalah and ideas that were to ripen under Kant's influence.