Pink tourmaline is a birthstone of October, along with opal, and is a truly special gem. The deep rosy color of a pink tourmaline ring will be sure to attract attention. One of the oldest gemstones in history, garnet is the birthstone of January. Garnet rings have been popular since Victorian times, and are treasured for their deep red color. The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights.