Which highly prized form of carbon is the hardest natural material?

A highlight of Berlin's Egyptian Museum is the 3,300-year-old bust of which queen? A highlight of Marie Antoinette's day on September 19, 1783, was watching a sheep, a duck and a rooster do what? A highlight of the Great Lakes Shipwreck Museum is the bell from which ship that sank in 1975? A highlight of which 1956 film is Marilyn Monroe, as saloon singer Chérie, singing "That Old Black Magic"? Which hiking route runs from Maine to Georgia? Thimphu is the capital of which Himalayan kingdom? Which word names both a Hindu holy man and a Yankees great? A hinny is the offspring of which two animals?