The power of the gavel and those who wield it

Picture of former Georgia House Speaker Tom Murphy by the Associated Press

Now that health reform has passed its latest hurdle, newspapers' feature writers are getting in on the action.
The Washington Post has this interesting story about the history and symbolism behind the three gavels House Speaker Nancy Pelosi used to signal the final moments of the health care debate in the nation's capital this weekend.
The article also gives some insight into the history of the gavel in the United States and its meaning in modern politics.
Those of you in Atlanta can go to the Capitol Museum on the top floor of the state Capitol to see one of the gavels used by the state Speaker of the House, which looks like a wooden Foster's Oil Can on a stick to me. Now that we know all this, I'd be interested to know a little about the wooden block that is struck by the gavel, ie. is it made of a certain kind of wood?, how often is it replaced?, etc.