... line on the back surface.Popular granite stone colors for window sills:G602, G603, G664, G687, G635, G636, G614 ... lintel, and stone mullions, which are compatiable with the window sills.In addition, we can also supply you other ... , quoins, string course, coppings, paving stones, countertops, slabs, tiles, tombstones, kerbstones, cube stones, etc. Window Sills (Granite Window Sills, Granite Threshold)