What metal is lighter than aircraft grade aluminum??

My friends ,friends,friends father gave him a piece of metal before he passed . It is square, about the size of a credit card, and extreemly thin. It looks like aluminum but is lighter than a business card of the same size? It is very strong and very hard to bend and about the thickness of a credit card. He said... show more My friends ,friends,friends father gave him a piece of metal before he passed . It is square, about the size of a credit card, and extreemly thin. It looks like aluminum but is lighter than a business card of the same size? It is very strong and very hard to bend and about the thickness of a credit card. He said his dad worked on jets*parts and stuff? what do you think this metal is????Aluminum????
Update: regular aircraft aluminum would bend and titanium is gold in color. This is aluminum color and so strong I cant bend it??? The thickness of a credit card and lighter than a paper business card!!?????
9 answers 9