Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller’s earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite

Elmore AR; Cosmetic Ingredient Review Expert Panel
Int J Toxicol. 2003;22 Suppl 1:37-102

https://www.ncbi.nlm.nih.gov/pubmed/12851164