Pink Tourmaline engagement rings? Absolutely! Diamonds may be a girl's best friend, but Pink Tourmaline engagement rings are a unique, original, and a far more affordable choice. 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. 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.