The blue variety of corundum is called sapphire. It ranges from a very light to very dark violet blue to greenish blue. It is the birthstone for September and given on the 5th and 45th wedding anniversary. Major sources include Myanmar, Sri Lanka and Thailand. Many believed Earth rested upon a sapphire and that is why our sky is blue. In modern times, Sapphire gained popularity after Prince Charles of Whales gave Lady Diana a sapphire engagement ring. After Princess Diana’s passing, Prince William gave it to Kate Middleton, his wife today. Sapphire is collectively recognized as the gem of truth, faith, and loyalty. It is also believed to help relieve headaches and vertigo.