I agree with monoloco. I am no expert by any means but this looks quite similar to
Graptopetalum paraguayense raptopetalum paraguayense Walther 1938 (Ghost Plant)
This species has rosettes of thickened, ovate purplish-grey leaves on thick, sprawling stems. Leaves fall off readily and may be used to propagate new plants. Small clusters of white flowers, with tiny red spots, are produced in the Spring.
Known from a single locality up to 2500ft in the Mexican mountains and moderately hardy. The leaves are edible and used in Taiwan traditional medicine to regulate blood pressure.
Source
www.succulent-plant.com
Even if this is correct I am puzzled by the notes that this is found in a single location in Mexico but has been used in traditional Taiwanese medicine. How did the Taiwanese know about it?