“It’s a stunning 3.5-carat round-cut diamond in a solitaire setting,” according to UK jeweler Zack Stone. “But Emma has opted for a thick gold band, which is an unconventional choice since most people favor a thin band in order to accentuate the size of their diamond. It’s a timeless choice for an engagement ring, symbolic of eternal love.” Roberts selfied this bucolic announcement in a puff-sleeved Dôen top—the same blouse Taylor Swift owns in pink—with an enormous grin. (A sizable engagement ring will do that to a person.)