The world’s most valuable private jewellery collection will go on display in London from Saturday before what is expected to be a record-breaking £120m charity auction. The more than 700 items of jewellery collected by the late Austrian billionaire art collector Heidi Horten is on a world tour, taking in New York, Singapore, Taipei and London, in the run-up to a four-part auction at Christie’s in Geneva next month and online. Some of the top pieces will be on public display at its St James’ auction room in central London from Saturday until Wednesday. The collection includes a white gold and diamond Cartier ring set with the Sunrise Ruby, the world’s most valuable non-diamond gemstone, which Horten bought for $30.4m (£24.5m) at auction eight years ago. The 25.59-carat rare “pigeon’s blood” Myanmar ruby is described by the Swiss Gemmological Institute as a “unique treasure of nature” and is expected to sell for $15m-$20m. Also up for auction are the Briolette of India, a 90.38-carat colourless diamond cut by the jeweller Harry Winston and a three-strand natural pearl necklace with an 11-carat pink diamond clasp estimated to sell for $7m to $10m. In total the collection is expected to fetch more than $150m (£120m), making it the most valuable set of jewels ever sold at auction – eclipsing the $116m Elizabeth Taylor’s sold for in 2011 and the $109m sale of the Qatar’s ruling Al Thani family’s in 2019. Rahul Kadakia, Christie’s international head of jewellery, described Horten’s treasures as “the collection of a lifetime”. “From Bulgari to Van Cleef & Arpels, from a small personal memory piece to the Briolette of India, this is a collector’s dream,” he said. Horten – who inherited an estimated £2.7bn when her husband, the department store magnate Helmut Horten, died in 1987 – died in June 2022 with no direct heirs. Concerns have been raised about the source of the family fortune, including allegations that Helmut Horten acquired assets from Jewish people who had had their property confiscated by the Nazis. A Horten collection commissioned report by historians at the University of Würzburg found he “benefitted from the economic circumstances provided by the Nazi state. He did not, however, take active steps to exert pressure on the Jewish sellers.” All the proceeds from the Christie’s sale will go to the Heidi Horten Foundation, which she set up in 2020 to fund a public art museum in Vienna to hold her vast art collection and to fund medical research. Horten died just days after opening the Heidi Horten Collection museum, which includes pieces by Francis Bacon, Gustav Klimt, Damien Hirst, Egon Schiele and Pablo Picasso. A keen ice skater in her youth, Horten was a lifelong ice hockey fan and supported the Austrian team EC-KAC to which she reportedly donated €3m (£2.7m) a year. The team has named its new stadium after her.