“These under-$500 14k gold and diamond pieces are perfect for the self-purchaser.” —Managing editor Melissa Rose Bernardo             1. I wear two of these dainty diamond bar rings every day, and I can’t wait to add more to my stack. (Dana Rebecca, $330 each, danarebeccadesigns.com)   2. This open cuff is bang on trend, but the classic design, dotted with a single diamond, ensures it’ll never go out of fashion. (Loren Stewart, $495, lorenstewart.com)   3. The shining star in your life deserves th