The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights. Gem of hot summer nights and steamy red sunsets, ruby is the birthstone of July. Show the world the passions within you with a fiery ruby ring. 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.