Topaz
Al 2%, F 1%, H 1%, O 5%, Si 1%,

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) = 182.05


Minerals may vary in elemental composition and impurity levels. The formula given is an approximation.
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Topaz
is defined with respect to the entities below:
The entities below are defined with respect to:
Topaz
Mineral (generic)


chemical compound molecule metal molecular science reaction mechanism ionic material acid base geometry reactivity synthesis science knowledge chemistry Lewis