I had never heard of it, but since no one responded, I did look it up. Very interesting little plant, actually in the same family with moss roses.
I can see why you are having trouble finding it. I found it on a list of rare and unusual succulents.
These folks are advertising them for sale
https://www.aridlands.com/catalog/product_info.php?products_id=1882&osCsid=c321437fdro7bghef8ueovjhk2 "arid lands greenhouses"