Fire Opal engagement rings? Absolutely! Diamonds may be a girl's best friend, but Fire Opal engagement rings are a unique, original, and a far more affordable choice. This birthstone of October embodies the orange and red colors of a warming fire. The fiery sparkle of this gem makes a fire opal ring become the center of conversation The birthstone of May, an emerald ring symbolizes the eternally returning spring. The velvety green color of emerald is a perfect match for spring and summer fashions.