A Christie's staff holds a 18.96 carat Fancy Vivid Pink Diamond during a preview in Geneva, November 8, 2018. 

Christie's puts under the hammer next week the largest fancy vivid pink diamond that the famed auction house has ever sold, expecting to fetch $30 million to $50 million for the nearly 19-carat, rectangular-cut gemstone.

The "Pink Legacy" will be the standout offering at Christie's fall jewelry auction in Geneva on Tuesday.