This plant from the thick-leaf family, described in 1919, comes from the Mexican state of San Luis Potosi.
The species name oviferum means "raw egg". This means that the white, frosted, egg-shaped leaves are easily detached from the trunk.
These leaves look like stones, hence the name "moonstone".
The shoots grow upright at first, later hanging and are up to 20 cm long.
The inflorescence becomes approx. 10 cm long and bears several, cup-shaped flowers.
The flowers themselves are greenish-white and open only a little. Then you can see the red, inner petals.
Plants about 6 cm in diameter, about 5 cm tall