The graphite form of carbon consists hexagonal sheets of carbon atoms, with benzene-like bonds around each ring. Graphene is the hot new notion of working with just a single layer of this stuff, rather than the trillions of layers that make up even a very shin sheet of graphite. Since this quilt shows just one layer of atoms, it's a graphene quilt. (Note that, unlike all the other molecule quilts, this one does not include element symbol letters inside each atom. They are all carbon, so the letters would be redundant.)
I do not advise choosing any lettering on this quilt. It will not look good.
(Click the image to see more picture. When you order the quilt you'll be given options for fabric, thread color, and lettering.)