Christie’s sale of Heidi Horten’s collection confirms that the Austrian collector’s cache of gems is the largest and most valuable private collection of jewellery ever to come to under the hammer. The pre-sale estimate for the Heidi Horten collection is US$150 million. The most valuable jewel in the Heidi Horten sale is the ruby and diamond ring by Cartier (lot 96). The 25.59 carats ‘Sunrise Ruby’ is a highly desirable saturated pigeon blood red colour. Spanning the 1970s through to the 1990s Heidi amassed 700 pieces of jewellery and until the very end was still buying jewels.