Cate Blanchett's Tiffany & Co. Necklace in 2015 Cate's turquoise and aquamarine Tiffany & Co necklace stood out against her black Maison Margiela by John Galliano dress on the red carpet in 2015. Her chunky necklace was from the 2015 Blue Book and is beautiful from every angle. Image Source: Getty / Frank Trapper