A belt for an elevator system includes a plurality of tension members arranged along a belt width and extending longitudinally along a length of the belt. Each tension member includes a plurality of basalt fibers to enhance temperature resistance of the tension member. A jacket material at least partially encapsulates the plurality of tension members. An elevator system includes a hoistway, an elevator car located in the hoistway and movable therein, and a belt operably connected to the elevator car to suspend and/or drive the elevator car along the hoistway. The belt includes a plurality of tension members arranged along a belt width and extending longitudinally along a length of the belt. Each tension member includes a plurality of basalt fibers to enhance temperature resistance of the tension member. A jacket material at least partially encapsulates the plurality of tension members.