Some of the unusual Southern African genera—such as Conophytum, Lithops, Titanopsis and Pleiospilos (among others)—resemble gemstones, rocks or pebbles, and are sometimes referred to as 'living stones' or 'mesembs' (short for mesembryanthemums).

The APG II system also classes the former families Mesembryanthemaceae Fenzl, Sesuviaceae Horan.

[3] Glistening epidermal bladder cells give the family its common name "ice plants".

Flowers are perfect in most species (but unisexual in some), actinomorphic, and appear singularly or in few-flowered cymes developing from the leaf axils.

[10] The family includes many species that use crassulacean acid metabolism as pathway for carbon fixation.

Some species are edible, including: C. edulis was introduced to California in the early 1900s to stabilize soil along railroad tracks and has become invasive.