Author Archives: ajohnston

Image from http://fashionbride.wordpress.com/2008/10/25/love-is-in-the-diamonds/

Wish that you had some magic ingredients that would enable you to create a diamond that you could afford? Well, you probably already do! Diamonds have been created using only peanut butter as an ingredient. But don’t go running to your pantry too fast- it’s not as simple as that. Although, the majority of us can easily afford our favourite jar of peanut butter, turning this spread into diamond requires a process that is very costly.

Diamond formation in mantle
Image from http://geology.com/articles/diamonds-from-coal/

Diamond is an allotrope of carbon, meaning that it is one form in which pure carbon can be found; it is the hardest naturally occurring material found on Earth. Naturally, diamonds are formed under specific conditions. According to Dr. Hobart King, most commercial diamonds are formed in specific areas of the Earth’s mantle. Located just below the Earth’s crust, the mantle is a high-density section of the earth’s interior upon which tectonic plates of the crust flow. The mantle is a very thick layer of the earth (spanning from about 30km to 2900km below the surface); thus, it has a large temperature range of about 870°C to 2200°C. Under these high temperature and pressure conditions, diamonds are formed from carbon sources in the mantle. However, diamond will only form at very specific conditions within the mantle: at temperatures over 1050°C and at depths of approximately 150km below the Earth’s surface. At these depths, humans are unable to obtain the diamond. But, when rare deep-source volcanic eruptions occur, material from the mantle is brought up the surface of the Earth where it can be obtained by us humans. From this, we get diamonds.

Discoloured diamond
Image from http://multichrome.blogspot.ca/2012/06/diamonds-from-peanut-butter.html

Professor Malcolm McMahon, of Edinburgh University, has been able to create conditions that mimic the high temperature and pressure conditions of the Earth’s mantle.  McMahon explains that he created these conditions with the ‘stiletto heel effect,’ where in this case, peanut butter was squeezed in between the tips of two diamonds. Using this method, pressures of approximately 45 to 60 kilobars with temperatures of 900 to 1300°C were generated. Peanut butter, being made from primarily roasted peanuts, is a good source of carbon. So under these conditions, McMahon was able to transform peanut butter into diamonds. These diamonds are not perfect, however, as many impurities from the peanut butter cause the diamond to be discoloured. Nevertheless, the diamonds created have previously been on display as they could be a step in the direction of creating cheaper, synthetic diamonds from easily-accessible materials.

So, we have been able to create synthetic diamonds in the laboratory; but, currently it would not be economical to create diamonds from peanut butter as creating the conditions required to do this is very expensive. Who knows, maybe one day a cheaper alternative will enable us to do this for less. So appreciate your peanut butter, like the dog in the video below, knowing that it alone can be used to create diamonds!

Posted by: Angela Johnston