A tiara passed down through generations of Italy's royal family will be among the highlights at a Sotheby's auction of jewels in Geneva next week that will also feature the largest Kashmir sapphire ever to appear at auction –– a 55.19-carat oval gem. Dating to the second half of the 19th century, the tiara was a wedding gift to Maria Vittoria dal Pozzo upon her marriage in 1867 to Amadeo ...