Some people prefer to lead a low-key life, not wanting to invite attention to everything they own. Still, these celebrity engagement rings are noteworthy in their own right for the relatively modest diamonds.     Amy Adams Diamond Ring Even though it was designed by a world-class French jewelry designer and has flawless diamonds, the engagement ring of Amy Adams is relatively small and immaculately created. It is a 1-carat diamond ring with a halo of other diamonds held in place without prongs. There is a colored gemstone on the underside of Amy Adams engagement ring, selected specifically since it has a significance for her. Alyson Hannigan Diamond Ring Alyson Hannigan is also an extremely fortunate actress. On their tenth wedding anniversary, her husband proposed that they renew promises and gifted her a diamond ring to celebrate the occasion. It is a simple and sweet solitaire, set on a platinum band. Julia Stiles Diamond Ring Preston Cook presented Julia Stiles with an engagement ring featuring a contemporary style. It flaunts a rose gold band and a round-shaped diamond that is set in a bezel setting.