What Is Petrichor And Where Does It Come From

Petrichor (/ˈpɛtrɪkɔːr/) is the earthy scent produced when rain falls on dry soil. The word is constructed from Greek petra (πέτρα), "rock", or petros (πέτρος), "stone", and īchōr (ἰχώρ), the fluid that flows in the veins of the gods in Greek mythology. 

Petrichor is the term coined by Australian scientists in 1964 to describe the unique, earthy smell associated with rain. It is caused by the water from the rain, along with certain compounds like ozone, geosmin, and plant oils