Petrichor: Dust after Rain
Derived from the Greek word petros (stone) and ichor (the fluid that flows through the veins of the gods), petrichor is the name for the dewy, musky smell that accompanies the first rain after a dry spell. It’s partly emitted by rocks, clays and soils, which absorb oils given off by vegetation during the warm dry periods. When rain disrupts them, the oily scent is released. It’s as complex as a perfume, made of up at least fifty distinct chemical compounds, but it’s not the only contributor to petrichor—geosmin (pictured) is also responsible. It’s an organic compound that literally translates to “earth smell”, produced by cyanobacteria (blue-green algae) and actinobacteria (bacteria spores), and found both on soil and rocks. The human nose is incredibly sensitive to geosmin—we can detect concentrations as low as 5 parts per trillion. Now, I’d love to see a petrichor line of perfume.