Marble ceiling

http://www.urbandictionary.com/define.php?term=marble+ceiling&defid=2176635

Discriminatory barrier keeping a certain class of people out of an upper echelon of American government. Distinguished from a glass ceiling because not only is this class prevented from rising to the next level, they cannot even see what is going on up there.

Coined by incoming Speaker of the House Nancy Pelosi. "When my colleagues elect me as speaker on January 4, we will not just break through a glass ceiling, we will break through a marble ceiling." - Nancy Pelosi, Jan. 3, 2007.