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. Ruby signifies passion and unbridled, unrestrained love, making a pair of ruby earrings a perfect Valentine's day gift.