why is graphene unique? why is graphene unique? graphene is the thinnest and weakest known material. it conducts heat and electricity, it is transparent, and it is completely impermeable to all substances, including helium. graphene is the thinnest and strongest known material. it conducts heat and electricity, it is transparent, and it is completely impermeable to all substances, including helium. graphene is the thinnest and strongest known material. it does not conduct heat and electricity, it is transparent, and it is completely impermeable to all substances, including helium. graphene is the thickest and strongest known material. it conducts heat and electricity, it is transparent, and it is completely impermeable to all substances, including helium.