Petrichor is a relatively new word coined by two CSIRO scientists Isabel Bear and Richard Thomas who first described the word in the scientific journal Nature in March 1964. The word Petrichor is used to describe the distinct smell of rain in the air. A sweet scent that all pluviophiles know very well. Who can resist opening the kitchen window after that first rain to let in the sweet refreshing smell of petrichor?

In fact, it's not the scent of rain at all but a combination of an oil and a certain actinobacteria that is released from the earth into the air, typically just before rain begins to fall. Petrichor may be more potent in drier climates like Australia. The scent is often triggered after long dry spells or periods of drought when the soil is very dry. The Petrichor oil, as discovered by Joy and Richard, is released by the soil when it is exposed to moisture in the air through increased humidity.

The scent will eventually go away after the rain has passed and the ground begins to dry again. The mysterious oil will then lay dormant waiting to tell us when the next rainfall may be coming. Scientists now believe that our ancenstors may have used petrichor as an indicator of when wet weather was approaching which was imperative for their survival.

Interestingly the word Petrichor is derived from the Greek for stone, "petra" and "ichor" which many mythology and fantasy buffs will know as the ethereal blood of the gods!

The scent of rain has also become a popular fragrance for candles. Perhaps the next time I listen to some relaxing rain sounds I should try lighting one of these candles. Pluviophile bliss ...