LOS ANGELES (CBS) — An engagement ring stolen from a friend of murdered actress Sharon Tate is going on the auction block.

Tate’s sister, Debra, says she is outraged and calls the planned sale “extremely disgusting.”

In an exclusive interview with CBS 2, Tate’s sister says the antique ruby and opal ring was given to Sharon by film director Roman Polanski in the 1960′s.

He gave it to her when they met on a movie set and fell in love.

The ring was not on Tate’s finger when she was murdered by members of the Manson family in 1969, as previously reported by other outlets.

Sharon had given it to a friend, who said it later was stolen, her sister said.

The ring recently resurfaced on an auction house web site with a starting bid of $10,000.

“Here we are 42 years after and once again, the only thing that comes to mind is her death. I see it as re-victimizing the victim,” Tate said.

Its estimated value is between $25,000 and $50,000.