Kaeline's clay mask is a jar of taupe-colored, powdered hectorite. The instructions are a little vague: "mix some with warm water and argan oil to obtain a paste". Common sense and your own supply of argan oil are required. I mixed two teaspoons of the powder with a little Argarome Jour and water until I got a consistency that I hoped would stay on my face for the designated 20 minutes.
The mask, once rinsed off, had done an excellent job of removing excess oils and closing pores. Although the process is a bit messy, I would definitely use it again on those days when one's nose is in serious need of a touch up. Kaeline recommends using it for the hair as well. But I can't imagine why one would (the mineral content of hectorite is mostly magnesium and lithium and I haven't been able to connect either of them to hair care).