The whopping 48.28-carat, rectangular green-tourmaline ring at David Webb was the prettiest stone I’d seen all day. For a second, I considered a career switch to investment banking. Then I noticed the eighteen-karat yellow-gold setting which seemed very Joan Collins. Though the gold's hue was too mature for me at 23, I’d love this ring in a few decades. 789 Madison Ave., nr. 67th St.; 212-421-3030.