Emerald engagement rings? Absolutely! Diamonds may be a girl's best friend, but Emerald engagement rings are a unique, original, and a far more affordable choice. 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. The birthstone of December, the tranquil azure color of a blue topaz ring can evoke thoughts of warm Caribbean seas on a cold winter day.