From southern Namibia and South Africa, Crassula rupestris is a branching succulent sub shrub very similar in appearance to Crassula perforata. It has thicker, rounder leaves. In summer in bright enough light the leaves can take on a reddish tinge. Pale pink flower cluster appear in late summer.
I tried some of this in the ground last year, it didn't make it. So far I haven't been able to give it enough light to turn red.