I use a few different clays but my most favourite is rhassoul clay. It comes from the Atlas Mountains in Morocco and is formed through geothermal changes and volcanic activity.
Rhassoul clay is highly absorbent and is widely used in beauty care products. When mixed with water it swells in size. It has high levels of silica and magnesium and helps cleanse the skin without stripping it of its natural oils. It is often used with oily or blemished skin as it helps draw out impurities like blackheads without damaging the skin.
Rhassoul is also beneficial for your hair. This is how I use it most often! I use a mix of rhassoul, rose water, regular water, horsetail extract, and rosemary essential oil. I make a paste that I massage into my scalp and hair each morning in the shower. I let it sit for a few moments and then rinse it off. It is important not to let it dry on your hair as that can damage the hair. But used wet it does a great job of cleaning my hair and scalp and leaves my hair soft and easy to manage. I also find that I get less static fly away hair in the winter now.
It is not a clay to be taken internally as it has a very high mineral content. If you are considering taking it internally, you should check with a doctor.