Clark Griffith-Baseball Hall of Fame 1946

I have three items that came together and I am trying to find further information about one item in particular.

First is a personal letter signed by Clark Griffith to Drucie Snyder (Daughter of the Former US Treasury Secretary and best friend of Margaret Truman). The letter is on Washington Nationals (American League)letterhead and dated November 9, 1950.

With this letter I also have a small wooden pendant which is shaped and painted like a baseball. The pendant unscrews and there is a small square white piece of hard material inside. Do you have any idea what this is?

The third piece is a 1961 American League annual pass to all grounds made out to John Horton and One. The serial # is 56 MI. These are all in near excellent condition.