Just the right jewelryDiamonds are a girl’s best friend for a reason: they’re striking, sparkly, and sophisticated. While your jewelry collection doesn’t have to include high-priced stones or platinum settings, it should include at least one truly special piece that speaks to your personal style — be it classic, preppy, edgy, or a combination of many looks. If there’s a piece you’re going to wear every day, it’s worth spending the money (and time) to get exactly what you want. Our pick: gold and amethyst necklace, $750 at Persona Jewelry (504 Comm Ave, Boston, 617.266.3003).