Sometimes the best designs are the simplest designs. These rings focus on the beauty and brilliance of the gemstones and the sheen of the 14K gold that encompasses them. This birthstone of October has a luminosity and glow that makes an opal the treasure that it really is. The rainbow of colors on a neutral white background makes an opal ring a perfect match for any outfit. The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights.