To see a world in a grain of sand and heaven in a wild flower, hold infinity in the palm of your hand and eternity in an hour. -William Blake. Your spirituality is on display with Sapphire infinity jewelry. Sapphire is the birthstone of September, and one of the most popular gemstones on the jewelry scene today. The deep blue color of a sapphire ring is just right for an evening out. 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.