When the Austrian philanthropist Heidi Horten died in June 2022, her jewelry collection numbered over 700 objects: among these were the Sunrise Ruby, the world’s most valuable non-diamond gemstone, and the Briolette of India, a 90.38-carat colorless diamond. Now the glorious assemblage will be offered as a sale series. Bulgari, Van Cleef & Arpels, Harry Winston, Cartier, and Tiffany are just some of the places she shopped. This is one of the largest jewelry auctions to date. —Elena Clavarino