Ah, those lovely "silver skins"--not so easy to grow, but so unique and beautiful. One of their colloquial names is "bababoudjies", or "baby bottoms"!
Argies come from the northwestern part of the Western Cape Province in South Africa. They like quartz gravel flats and sunny hillsides. They must be kept very dry in summer, and a little shaded. They'll wrinkle up a bit, but fear not, when they come out of dormancy, they plump up like these.
I can't stress enough how Argies don't like much water. If you take a closer look at the central clump, you'll see what happens if they have too much.