Once considered more valuable than diamonds, a peridot ring is a must have. This "gem of the sun" is the birthstone of August and is a beautiful match for the lush green tapestry of late summer. 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.