Phillips New York Jewels Auction will have signed jewels by Tiffany & Co., Van Cleef & Arpels, Bulgari and Chaumet, as well ...

“Fluorescence is a natural birthmark of a diamond that adds curiosity and wonder,” says Jason Quick, the executive director of American Gem Society ... ‘four Cs’ — cut, clarity, color ...

The one-of-a-kind gem was reset in 2012 into the necklace ... gown with 16.46-carat yellow diamond drop earrings and a radiant-cut yellow diamond ring, both by Harry Winston.

The Italian maison’s new Allegoria collection of high jewelry showcases rare and surprisingly large gemstones, including a 226-carat vibrant cushion-cut green tourmaline and a 78-carat radiant ...