Graphene is just one particular arrangement of the many that carbon atoms can adopt
It does occur naturally in graphite, but in tiny segments.
Thus graphene will be present in powdered graphite,
but in powdered form, graphene is pretty much indistinguishable from any of the other arrangements of carbon atoms found in graphite.
The wonder of graphene happens when larger sheets are made, then its superior physical properties can be observed.
Then perhaps it's not graphene. when I mix graphite powder with h2o, mg sulfate and citric acid, only a tiny amount of "graphene" starts to form. Looks kind of shiny silver color to me. I tried adding a small amount of magnesium metal and it bubbled carbon dioxide gas (was done outside) then a layer of very shiny silver material formed on the top. Maybe it's just mg metal or something? Wondering if it's just mg metal on surface, why did it all not all dissolve in the citric acid