Ruby engagement rings? Absolutely! Diamonds may be a girl's best friend, but Ruby engagement rings are a unique, original, and a far more affordable choice. Gem of hot summer nights and steamy red sunsets, ruby is the birthstone of July. Show the world the passions within you with a fiery ruby ring. 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.