As with the Tiffany Diamond, the rare appearance of this ... To see her subtle shift, compare the necklace Lady Gaga is wearing tonight to the Medusa necklace on view at the Tiffany Landmark ...

It's been 15 years since Lady Gaga made her Grammys ... swaths of fabric draping throughout. Gaga committed to the Vampire-chic bit with a Tiffany & Co. necklace from the brand's 1930s archive.