Vermiculite is expanded mica.
Mica schist are metamorphic sedimentary rocks ... usually changed by compression and heat from shale. As such, the shiny mica layers are sometimes interspersed with other sedimentary stuff like talc, asbestos, etc. Sometimes the layers between the shiny mica are feldspar. Depends on the mine source.
Talc sometimes has asbestos in it too. Some sources of talcum powder used to have asbestos in it. Some sources of vermiculite did too. The danger is in the breathing in of the asbestos, not necessarily in eating it. However, I would hope the responsible regulatory agencies have eliminated asbestos from commercially available talcum powder and vermiculite.
PV
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