Examples of specific types of clays from the smectite mineral group include: hectorite (SHCa-1, the Source Clay Minerals identification code) (provided by Source Clay Minerals Repository, University of Missouri, Columbia, Mo.) with a C.E.C.=43.9 meq/100 gms and S=63.2 m2 /gm; Cheto montmorillonite (SAz-1) with a C.E.C.=120 meq/100 gms and S=97.4 m2 /gm; Washington montmorillonite (SWa-1); Wy