A rare grey pearl necklace that once belonged to a British aristocrat sold for HK$41m ($5.3m; Â£3.5m).
Meanwhile, a 27.68-carat Kashmir sapphire and diamond ring, The Jewel of Kashmir, sold for HK$52.28m.
Both pieces of jewellery were bought by Hong Kong collectors on Wednesday, Sotheby's announced.
The string of pearls was part of the collection of Viscountess Cowdray, Lady Pearson, famous for her collection of art and furniture as well as jewellery.
The previous world auction record for a natural grey pearl necklace was set in London in 2012 when the Cowdray Pearls sold for $3.35m.
A string of natural grey pearls and a Kashmir sapphire broke world records at an auction in Hong Kong, auctioneers Sotheby's say.