Bentonite is one of most popular clays and comes from naturally occurring volcanic ash sediments here in the United States. Bentonite clay has been traditionally used to assist in mineral deficiencies, and to help bind toxins making them more soluble. Bentonite, also referred to as Montmorillonite, is one of the most effective and powerful healing clays. Bentonite can be used externally as a clay poultice, mud pack, or in skin care recipes. A good quality Bentonite should be a grey/cream color, and anything bordering ?pure white? is suspect.