Small genus containing less than 20 succulent species in the Crassulaceae family. Some species in this genus are commonly called Moonstone, after their attractive rounded and fleshy foliage. This is usually coloured green and may develop a red, purple or pink colouration under good lighting. Other species have more pointed leaves and all are succulent, holding water in their leaves. They produce slightly pendulous, lantern-shaped flowers in a range of colours including pink, red, cream and yellow.