A mesmerising collection of jewellery will be up for auction next month in Geneva. The pieces, ranging from the late 18th century to the present, belong to Lily Safra, a Brazilian socialite and philanthropist. Collectors in London, New York and Paris have previewed the collection, which will be in Hong Kong on Friday and Saturday at Christie's in Alexandra House. Francois Curiel, international head of jewellery and Asia president for Christie's, declares it 'a sublime collection of 70 rare jewels comprising the very best in all styles, periods and makers from the late 18th century all the way to modern times'. He says the collection is attracting worldwide attention. According to Curiel, who will be pounding the hammer in Geneva on May 14, Safra has decided to sell the best pieces of her collection and donate the proceeds to 20 charities for children in Rwanda, a children's hospital in Israel, Le ballet de l'Opera national in Paris, the study of Parkinson's disease at New York University, and the Royal Opera House in London, among other recipients. 'Only a connoisseur with an eye as refined as that of Lily Safra could have collected such an ensemble of jewels, and only someone with her philanthropic conviction could have expressed such powerful support to worthwhile causes,' Curiel says. The sale is called 'Jewels for Hope' and Curiel says each piece has top-quality design and stones. The auction is expected to fetch more than US$20 million. The highlights are 18 pieces by JAR, the largest private collection of pieces by Joel Arthur Rosenthal ever to be auctioned, alongside diamonds, rubies, sapphires and antique, and period jewellery. Curiel has known Safra for decades and is familiar with many of her pieces, some of which were acquired through auctions. He knows she is a good friend of Rosenthal, but he was unaware of how many of the jeweller's pieces she had amassed. 'Joel likes her and, when he designs pieces for her, he bears her personality in mind,' Curiel says of the low-key designer who creates 70 to 80 jewels per year from his Paris shop for exclusive clients. The results are stunning pieces, such as a ruby and diamond camellia flower brooch and another featuring a pink and green tourmaline poppy flower with its stem wrapped around a pear-shaped diamond. Safra met Rosenthal in 1981 after her late husband, banker Edmond Safra, acquired a 37ct pear-shaped diamond at a Christie's auction. 'She was not interested in the usual necklace, pendant or ring traditionally designed for such a gem,' Curiel says. 'She approached Rosenthal, who imagined the diamond entwined in the stem of two tourmaline poppy flower heads forming a brooch. This was the beginning of their creative friendship, based on a common sensitivity and sense of perfection.' Other notable pieces are an oval-shaped Colombian emerald, surrounded by natural pearls and diamonds, and a set of three diamond eternity bands where the diamond points are facing outwards. A sapphire and diamond cuff was designed by Suzanne Belperron, whom Curiel describes as the Joel Rosenthal of the 1930s. A set of 12 antique diamond leaf brooches and a pair of ear clips date from the mid-19th century. Curiel recalls going to one of Safra's dinner parties and seeing these brooches scattered on the dining table as decoration. There will also be 16 Faberge silver-gilt and guilloche enamel menu holders up for auction. Gem collectors will be keen to get their hands on the stones Safra has collected in the past five decades. The top one and Safra's most emotional piece will be the 34.05ct rectangular-cut diamond ring that was a wedding present from her husband in 1976. Others include a 32.08ct cushion-shaped Burmese ruby and diamond ring by Chaumet and a 31.21ct rectangular-cut Burmese sapphire and diamond ring mounted by Boucheron. Safra's antique pieces include a Colombian emerald and diamond two-row necklace from the late 19th century, and two Belle Epoque necklaces designed by Cartier: one is a diamond and emerald flower necklace with leaves, the other like a bow with diamond-studded strands hanging from it. A collector usually keeps her jewels for 40 to 50 years and then sheds the pieces by giving them to the next generation or putting them up for auction, Curiel explains. While some pieces were specifically designed for Safra, particularly the JAR pieces, Curiel says jewellery designers know pieces are passed on to others, thus giving them another life and a continuation of their history and provenance.