Sapphire is the birthstone of September, and pink sapphire is a very popular gemstone in jewelry today. The bright and happy color of a pink sapphire ring is both playful and trendy. Brown gemstones are gaining in popularity and smoky quartz is an affordable choice. A smoky quartz ring goes well with autumn colors and evening wear. 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.