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. November's birthstone, citrine sparkles like honey. Carry the warmth and glow of a golden sunset with you by wearing a beautiful citrine ring. The birthstone of December, the intense deep blue color of a london blue topaz ring can evoke thoughts of warm Caribbean nights.