Chlorite group
H 8%, Al 6%, Fe 2%, Mg 2%, Si 4%, O 18%,

estimated elemental composition and molecular weight 
Minerals with the same name may vary widely in appearance and composition, and very few are >99% (reagent grade) pure.

Gram formula weight (molecular mass) = 730.58

Minerals may vary in elemental composition and impurity levels. The formula given is an approximation.
Wikipedia Page:

Chlorite group
is defined with respect to the entities below:
The entities below are defined with respect to:
Chlorite group
Mineral (generic)

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