Ruby signifies passion and unbridled, unrestrained love, making a pair of ruby earrings a perfect Valentine's day gift. A pair of black onyx earrings are an affordable and elegant gift. Always appropriate and always in style, black onyx should be in every jewelry box. 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.