Crassula atropurpurea is a succulent shrublet, its branched stems may be woody low down. The height achieved is rarely as tall as 60 cm, much of it contributed by the tall flower panicles.
The leaves are paddle-shaped, sometimes finely hairy. They may be green or greyish green with margins red and cartilaginous.
Variability associated with the plant's distribution from Namaqualand in the Northern Cape to the Eastern Cape is confirmed by the existence of six recognised varieties.
All six of them are considered unthreatened in habitat early in the twenty first century (Manning, 2007; Smith, et al, 1997; Bond and Goldblatt, 1984; http://redlist.sanbi.org).