Shibao Shan, or Stone Treasure Mountain, is the strongest excursion from Shaxi: a protected mountain area of old forest, temples, grottoes, and long views over the valley. It was one of the first places in China to receive official protection, and it still feels like a religious landscape rather than a single sight.
Baoxiang Temple and Shizhong Temple are the main stops. Distances inside the area are larger than they look on a map, so leave enough time or arrange transport between the farther temples.