The opera glasses Abraham Lincoln held when he was fatally shot at Ford's Theatre in Washington on April 14, 1865 are on the auction block.

Lincoln carried the opera glasses to a showing of the play "Our American Cousin" when John Wilkes Booth burst into the president's theater box and shot him in the head with a pistol at close range.

According to Los Angeles-based Nate Sanders Auctions, the black and gold German-manufactured opera glasses later were found in the street by Army Captain James McCamly as he helped to carry Lincoln to the nearby Petersen House, where the president died hours later.

"The glasses remained in McCamly's family for three generations," the auction house said in a press release. "In 1968, the Ford's Theatre National Park Collection informed McCamly's great-grandson that they housed the carrying case into which these glasses fit 'precisely.'"

In 1979, the opera glasses were purchased by Malcolm Forbes Sr, heir of Forbes magazine. They are expected to sell between $500,000 and $700,000, the auction house said.

The opera glasses are being sold through an Internet auction that ends April 30.

[Lincoln bill in macro shot via]