Babe Ruth's 500th home run bat is shown before it goes up for auction by SCP Auctions in Laguna Niguel, California, November 25, 2019.

It's not the first time that one of Ruth's bats broke the million-dollar mark. A bat used by Ruth in 1923 to hit the first home run out of the original Yankee Stadium sold for a record $1.3 million in 2004.

A piece of Babe Ruth memorabilia that was given to a friend 75 years ago sold for more than $1 million at an auction over the weekend, according to a California-based auction house. The bat fetched $1.08 million from an unidentified buyer, according to SCP Auctions CEO David Kohler.

Babe Ruth's 500th home run bat is shown before it goes up for auction by SCP Auctions in Laguna Niguel, California, November 25, 2019.

Ruth's 500th bat was a gift he bequeathed to the former Mayor of Suffern, New York, Jim Rice, back in the mid-1940s. Ruth befriended the former politician, says Rice's son, Terry. The pair would often golf and go bowling after Ruth retired from baseball in 1935.

"They saw each other just about every day," Terry told CNBC in an interview.

Terry and his sisters Pam and Patricia stored the bat in the family home for years and wouldn't even tell friends about it, fearing it could get stolen. Terry said the bat was often stored in a closet.

"It actually became more of a burden," Terry said. "We were concerned about it; we had to insure it. We figured maybe somebody else could appreciate it."

Terry, who practices law in New Jersey, said the family insured the bat for more than $1 million.

Ruth's personal items have fetched high prices at auctions. His 1928 to 1930 road jersey sold for a record $5.6 million earlier this year by Hunt Auctions.

"Babe Ruth is king in the sports memorabilia business," Kohler said. "We feel (the 500th home run bat) has a very good chance of breaking the record."