The birthstone for the month of September is the sapphire. A gemstone variant of the mineral corundum, sapphires have a large range of colors, but the most identifiable is blue.
Other sapphire colors include white, green, yellow, orange, brown, pink, purple, gray and black, but never red. A red corundum is known as a ruby. A sapphire with an asterism that creates the appearance of a six-ray star is known as a star sapphire.
Sapphires are the traditional gift for a 45th wedding anniversary. The Logan Sapphire is one of the largest-known sapphires; it weighs 423 carats and is on display at the Smithsonian National Museum of History.