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. 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. 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.