Provided is a translucent ceramic which has a high Abbe number, is advantageous in aberration correction, and can be easily produced. The translucent ceramic contains, as a main component, a garnet type compound represented by the General Formula: Y.sub.3Al.sub.vO.sub.w, wherein the condition of 4.4.ltoreq.v.ltoreq.5.4 is satisfied and w is a positive number for maintaining electrical neutrality, in which the Al is partially or entirely substituted by Ga and the Y is optionally partly substituted by Gd. The translucent ceramic is suitably used, for example, for lenses arranged with a diaphragm interposed therebetween in a Gauss lens optical system, such as an optical system for single-lens reflex cameras.