Sapphires are one of the most precious, historically important and valuable gemstones. Sapphires are valued for their strong luster (ability to reflect light like a mirror), and hardness: they are the next hardest stones after diamonds. This means they can be worn in rings and bracelets for centuries with a low chance of being scratched. Sapphire is the birthstone for those who are born in September. It is also used to celebrate the 5th and 45th anniversary.