The final price was well above the $10,000 starting bid.
The auctioneers have a letter signed by Polanski verifying their tale.
Sharon Tate's younger sis, Debra, has objected to the auction, finding it morbid and "extremely disgusting," Los Angeles TV station CBS2 reports.
"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," Debra said.
She also disputes the auction house's claims about the ring.
Debra denies the ring was an "official engagement ring," maintaining instead that it was merely an "unofficial symbol of Sharon's relationship" with Polanski.
Debra, who manages the official Sharon Tate fan website, also tells CBS2 that her sister was not wearing any jewelry on the night she was killed.