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 variably paddle-shaped, sometimes finely hairy. They may be green or greyish green with margins red and cartilaginous, sometimes red all over.
Variability associated with the plants distribution from Namaqualand in the Northern Cape to the Western Cape and the Eastern Cape is confirmed by the existence of six recognised varieties.
The habitat of these plants varies, often growing exposed on rocky slopes with scrub or grass. The habitat populations of all six varieties are considered of least concern early in the twenty first century (Smith, et al, 2017; Manning, 2007; Smith, et al, 1997; Bond and Goldblatt, 1984; iNaturalist; http://redlist.sanbi.org).