Graphene forms rubbery hexagonal cell-based sheets - not 3D crystal structures. The edges of the sheets are in effect sharp because they are extremely thin. One can lay down multiple layers, but they are not true crystals. Graphene by itself does not form crystals as we know them, it has to be layered somewhat mechanically to form 3D structures.
Conventional crystals are defined by having three dimensional structures that they by themselves form, whether by crystallization from solution or under high pressure as in geological formation. For instance, diamond is the crystal form of carbon but graphene is the sheet form and doesn't quite fit that.
That is good, but recognize that graphene is NOT graphite. We are talking about different materials here. Diamonds, graphite and graphene are all carbon-based but their structures are each far different.
I don't think your definition is correct.
Graphene forms rubbery hexagonal cell-based sheets - not 3D crystal structures. The edges of the sheets are in effect sharp because they are extremely thin. One can lay down multiple layers, but they are not true crystals. Graphene by itself does not form crystals as we know them, it has to be layered somewhat mechanically to form 3D structures.
Conventional crystals are defined by having three dimensional structures that they by themselves form, whether by crystallization from solution or under high pressure as in geological formation. For instance, diamond is the crystal form of carbon but graphene is the sheet form and doesn't quite fit that.
https://www.britannica.com/science/graphene
That is good, but recognize that graphene is NOT graphite. We are talking about different materials here. Diamonds, graphite and graphene are all carbon-based but their structures are each far different.