The leaf rosette of Crassula alba seen here probably belongs to C. alba var. alba. There are two more recognised varieties, viz. var. parvisepala with conspicuous maroon or purple leaf spots and var. pallida, a threatened species of Mpumalanga and beyond the border in Swaziland. What the pallid version looks like could not be ascertained at the time of writing this.
Each plant will usually have just one rosette. Leaf pairs along the flower stems are spirally arranged. Some drying out of leaf tips is sometimes seen. Old dry leaves will remain on the stem. Leaf margins are sometimes folded in. The leaf surfaces are glabrous (hairless), although some scattered hairs are found on some plants.
There is a report from Swaziland that according to some traditional belief one can use C. alba for becoming invisible. Those with such a need should take care in experimentation to avoid unknown side-effects (JSTOR; http://redlist.sanbi.org; www.sntc.org.sz).