September's sapphire is the birthstone for the month of September. This gemstone is known for its stunning blue color, although it can also be found in other hues, such as pink, yellow, and green. Sapphires are a variety of the mineral corundum and are prized for their durability and brilliance, making them popular choices for jewelry. Sapphires have been associated with wisdom, loyalty, and nobility throughout history. They are often used in engagement rings and other fine jewelry pieces. The most valuable sapphires are those with a deep, vivid blue color, often referred to as "cornflower blue."