Fullers earth has been described and used in the west for long , however Multani mitti (clay) as it is known in Indian subcontinent is not studied in much details....Are they both made of same components or similar or are different ??
Fullers earth is a natural product and ia made of several components (aluminum silicates, clay-like...). Multani is used as a synonym. The composition depends to a certain extent on the location where the material was found.
Best way to answer your question: search for x-ray diffractograms of material from different abundances. Then you can compare.