Photo by Mary Levin The photo above shows the case that thieves had to unscrew in order to get at the valuable piece. A plaster cast of the crinoid that was stolen recently from the Burke.

The fossil — an underwater plant called a crinoid — is estimated to be at least 320 million years old and is about 1 square foot. It was stolen late Sunday afternoon while the museum was open. In part because of the rarity of the piece, Burke officials and the UWPD expect to solve the case.

“Collectors would certainly be aware that this is a rare piece,” Burke spokeswoman Natasha Dworkin said. “I think there’s a decent chance someone will be found.”

This is the latest in a string of thefts. A picture viewer that shows a repeating slide show was stolen earlier in the week. That item was valued at $400. A hard drive was stolen from a computer in the “Big One” earthquake exhibit. And a stuffed rooster from a Korean wedding display was stolen too.

Officials said security isn’t usually an issue at the museum. In fact, these are the first thefts at the Burke since 1989. But as a precaution, Dworkin said the Burke is operating under heightened security.

To report relevant information about the case call the UWPD at 206-543-0507.