[xyzzyz]

Graphite is "just carbon" too, but you cannot simply burn it by putting a lit flame to it -- it's simply not hot enough to combust it. To put it in perspective, graphite is frequently used as a crucible to melt aluminum in. Aluminum won't melt in your home fireplace (it's not hot enough), but graphite crucible will easily hold molten aluminum without combusting itself.

[DmenshunlAnlsis]

Graphite is also used to make rocket exhaust nozzles; it is really thermally stable stuff. Diamond by contrast is much easier to burn. The good news is that if you want to dispose of graphene, just stick it with a lot of other graphene and make pencils. It’s not as though we worry about disposing of pencil “leads” after all.