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. Sapphire is the birthstone of September, and pink sapphire is a very popular gemstone in jewelry today. The bright and happy color of a pink sapphire ring is both playful and trendy.