Is aluminum foil a metal?

Yes, foil is made from a single huge block of aluminum. The block is rolled between massive industrial rollers over and over again. The aluminum gets thinner and longer with each pass through the rollers until it is as thin as foil. For the very last 'roll' the foil is too thin to go through alone, so they put two sheets together, it is because of this 'double' final roll that the foil gets a shiny side and a dull side.

There are a number of posts on the web of short video clips a couple of minutes long showing the making of aluminum foil. YouTube and other sites have them. Use the link below to related questions.
Aluminium foil is made of the metal - aluminium., with a thickness of less than 0.2mm