A pair of sapphire earrings set in yellow or white gold is a classic, and is always appropriate. Choose from genuine sapphire, or the more affordable lab-created gem. Tourmaline is known as the gem of love and commitment. Buy her a pair of pink tourmaline earrings to seal the deal! A pair of peridot earrings sparkle by day, and remain brilliant at night. The Romans called peridot the “evening emerald†whose vibrant green color remained visible by lamplight.