How the Hunt for the Philosopher's Stone Led to Phosphorus

What glows in the dark, is flammable, and was first discovered in human urine?

While this substance may sound dangerous (and a little gross), it exists in foods we eat and in the world around us. We’re talking about phosphorus, the 13th element. Phosphorus is mainly produced in exploding massive stars, known as core-collapse supernovae. It is the 18th-most abundant element in the universe and the 13th-most abundant element in Earth’s crust.

Phosphorus is only reactive and unstable in its most pure form, and you’re unlikely to encounter it like that. It combines with other elements to create materials like apatite, the most commonly occurring phosphate mineral. Apatite is frequently used to date rocks and geological events that occurred on Earth’s crust, like studying the formation and evolution of mountains.

Apatite is also a key ingredient in fertilizers. Plants require phosphorus to live, using it for cell division, protein synthesis, and ultimately new growth. In fact, phosphorus is necessary for all living organisms to survive. Apatite, calcium and water form calcium hydroxyapatite, which is amajor component of the bones and the primary mineral tooth enamel of humans and other vertebrate animals; it's what gives bones their strength and hardness. We consume phosphorus in foods like meat, dairy, and grain (usually as a type of phosphate). So naturally, humans also excrete a form of phosphorus, and this is where we return to the original discovery of this element. 

Alchemist Hennig Brand discovered phosphorus in 1669. But it was an accident; he was hoping to find the Philosopher’s Stone, or a way to turn ordinary elements into gold. Acting on the belief that human urine might contain gold, Brand visited the local pubs to obtain samples in the form of beer drinkers’ urine.

Upon collecting enough of the liquid to test for gold, Brand distilled the urine and came up with a waxy substance instead. This substance not only proved to be flammable, but it gave off a pale-green glow. Hence, the name phosphorus means “bringer of light.”