  We employ room-temperature ultrahigh vacuum scanning tunneling microscopy
(UHV STM) and {\em ab-initio} calculations to study graphene flakes that were
adsorbed onto the Si(111)$-$7$\times$7 surface. The characteristic 7$\times$7
reconstruction of this semiconductor substrate can be resolved through graphene
at all scanning biases, thus indicating that the atomistic configuration of the
semiconducting substrate is not altered upon graphene adsorption. Large-scale
{\em ab-initio} calculations confirm these experimental observations and point
to a lack of chemical bonding among interfacial graphene and silicon atoms. Our
work provides insight into atomic-scale chemistry between graphene and
highly-reactive surfaces, directing future passivation and chemical interaction
work in graphene-based heterostructures.
