[Darryl Pitt] was talking about meteorites. Not just any old ones, but one that will be auctioned on Oct. 28, a 30 pound chunk sliced off one of the most famous meteorites in the world, the 15 and a half-ton one that Mr. Pitt was standing next to at the museum: the Willamette meteorite.

Once again, as it was at the opening of the museum’s Rose Center for Earth and Space in 2000, the Willamette meteorite is at the center of a brouhaha. An American Indian group in Oregon heard about the auction and accused Mr. Pitt of insensitivity for selling his fragment, which Bonhams, the auction house handling the sale, says has an estimated value of $1.1 million to $1.3 million.

The Indian group, the Confederated Tribes of Grand Ronde, considers the entire meteorite — which was found on their land in the Willamette Valley in 1902 — a sacred icon, so much so that it filed a claim in 1999 seeking its return. The museum countered with a lawsuit that asked a judge to declare it the rightful owner, and in 2000 a compromise was reached that left the meteorite in the museum. That deal came a little more than two years after Mr. Pitt got his chunk from the museum.

The tribe believes that selling off even a small piece is “highly inappropriate,” said Siobhan Taylor, a spokeswoman for Grand Ronde.

“We’re dismayed and hurt,” Ms. Taylor said. “To see that there are people who would take something that they know is held in such sacred esteem and barter it is a dismaying experience.”