This chapter examines ion-exchanged zeolites as precursors for the low-temperature synthesis of ceramics, with particular emphasis on the influence of key synthesis parameters, including the zeolite type, the ion-exchange process, and the heat-treatment procedure. Following an initial overview of the methodology employing zeolites as precursors for ceramic phase formation, along with a discussion of the early pioneering studies in the field, the chapter progresses toward the description of synthesis route for an advanced ceramic material. Particular emphasis is placed on the synthesis and crystallization mechanisms leading to the formation of the monoclinic celsian phase (BaAl₂Si₂O₈), a high-performance ceramic of significant technological interest. The discussion centers on ion-exchanged zeolites, especially Ba-exchanged forms of Zeolite A, X, and LSX and their thermal conversion into crystalline ceramic phases at comparatively low temperatures. The chapter explores the mechanisms of ion exchange of these zeolites, their thermal behaviour, and the effects of residual ions and mineralizing agents on phase transformation kinetics. Importance is placed on the ability of zeolite-derived amorphous phases to act as highly homogeneous and reactive intermediates, facilitating the crystallization of desirable polymorphs. In particular, the role of zeolite structure, chemical composition, and treatment parameters in directing the transformation pathway toward monoclinic celsian is critically analysed. Innovative approaches including microwave-assisted synthesis, sol-gel methods, and glass-ceramic routes are also reviewed, demonstrating the versatility and tunability of zeolites in modern ceramic engineering.