Phosphorus is sometimes referred to as "the Devil's element” because it was the 13th element to be discovered. It was isolated by Hennig Brand, a German alchemist who was searching for a method of creating the Philosopher's Stone. His attempt involved boiling hundreds of liters of urine, resulting in a small amount of white paste that could glow in the dark and burned very brightly. Hoping he could eventually turn the substance into the Philosopher's Stone, Brand kept the recipe a secret for six years before selling it to Daniel Krafft.
While Brand is usually given the credit for discovering phosphorus, it is possible that Arabian alchemists had already discovered it centuries earlier, using a similar method.
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