National Treasure Wiki
Meerschaum Pipe
Found Charlotte
Leads to "The legend writ, the stain affected, the key in Silence undetected, fifty-five in iron pen, Mr. Matlack can't offend."
Found by Ben Gates
"Is it a...billion dollar pipe? Is it a...million dollar pipe?"
Riley Poole[src]

The Meerschaum Pipe was found on the Charlotte. It is the clue that gave Ben Gates the idea about the Declaration of Independence. The stem of the pipe revealed a riddle when covered in an ink like liquid and rolled out on paper. But the pipe is also a key to open the treasure room.