On what is the "Mona Lisa" painted?

I know a guy who looks like the Mona Lisa . With that mysterious smile. He states at me in a weird way . I avoid him at all costs but love the painting

"Art historians believe that the woman who sat for da Vinci was most likely Lisa Gherardini, the wife of a wealthy silk merchant who lived in Florence in the 16th century, at the same time as the great Renaissance artist." - nbcnews.com

Terry B I never thought that possible