"terre de sommières"?

Ah, found a reference to it in a discussion board on stains:
"In France I was introduced to what they call terre de sommieres, which is a fine clay powder that is an absolute miracle for greasy stains on leather and suede. You just rub a bit of the powder into the stain, wait a few hours or overnight, and when you brush it off, the stain is gone. I've used it on suede bags, shoes, and leather coats. But I'm not sure what it would be called in the US -- if it exists here at all."

Sue