The paired, opposite leaves of Crassula vaillantii are simple and fused at the base around the stems. They are small, oblong to narrowly obovate, about flat above and rounded below with rounded tips. The blades may be concave on top and slightly upcurved.
The plant often appears to have a glut of stems and flowers while short on leaves (Smith, et al, 2017; Bond and Goldblatt, 1984; iNaturalist; https://savvastryfonosplants.com).