It may sound weird but still it looks like even peanut butter may shine one day. Currently scientists from the Bayerisches Geoinstitute in Germany are taking pains in finding what Earth's mantle is actually made of. Want they or not but it is closely connected with diamond formation. Though the composition of the last is known but it's still unbelievable how carbon can be transferred into the most solid stone in the world with the change of conditions.
The team of researchers lead by David Robson are studying possible constituents of lower mantle, because it's still unknown what it consists of. There exists much information on upper layers but lower layers are buried too deep under the ground to be studied. However, there are chambers in the laboratories where the conditions are very close to real. So they take certain materials and expose them to high pressure and high temperature to make them denser. Among the most odd materials peanut butter was taken. This is not a random choice. In fact this is a carbonaceous material which under heat and pressure turned into small diamonds.
Other carbon-saturated material is ash and hair/nail. These days it turns into a practice to make diamonds out of locks of hair as a long-lasting reminder of a person. The idea is that 'raw' material for making diamonds should be highly carbonaceous in order that under high pressure and extreme temperature it could dense into pure carbon.
While scientist are trying to explore the origin of the Earth's mantle and as a result to find how diamonds are made, the byproduct of their tests are more precious than they expected.