The leaves of Crassula muscosa are scale-like in appearance and tiny. They are densely overlapping, triangular in shape and neatly arranged up the many thin, often four-angled stems. The stems grow in dense profusion, much branched on the sprawling shrublets of up to 40 cm. The actual stems are hardly visible under their leaf coverings.

In some harsher parts of the vast distribution area across southern Africa, they are usually brown or grey in colour, otherwise fresh to pale green. The plant is found on rocky outcrops (Manning, 2007; Vlok and Schutte-Vlok, 2010; Bond and Goldblatt, 1984).