Aluminium has a shiny metallic lustre.
The specific gravity of aluminium is 2.72.
This is very low for metals. Only the alkali metals and some of the alkaline earth metals have lower specific gravities.
Aluminium is malleable and ductile. It does not display the characteristics of cleavage.
Aluminium is opaque.
However, all metals have a "skin depth". This is the depth to which electromagnetic radiation can penetrate the metal.
The skin depth of aluminium at 500 nm (green light) is about 3 nm. So a sheet of aluminium that is less than 10 atoms thick should be able to transmit some light.