The veteran actor wore the distinctive pointed ear to play his most famous character in the 1979 film Star Trek: The Motion Picture.
The iconic memento has been carefully preserved for more than 30 years and is now set to be sold off at an auction of Hollywood memorabilia next month (Apr11).
Dan Levin, a spokesman for Premier Props, the company behind the sale, says, "This ear was kept by the prop master from the film. It was carefully wrapped up which is important because silicone latex can deteriorate.
"Spock's ears are an iconic part of Star Trek and fans across the world would love to own it - we've already had lots of bids."
The auction will take place in Los Angeles on 2 April (11).
News of the sale emerged on Saturday (26Mar11) - the day of Nimoy's 80th birthday.