Petrichor.

That's the word that describes the smell of rain on dry earth. The term derives from the Greek words petra, meaning "stone" and ichor, which is the fluid that flows int he veins of Greek gods. The word was coined in 1964 by Australian researchers who found that the smell was created by an oil that is released by certain plants during dry periods. When it rains that oil is released into the air, giving us that wonderful smell that brings Spring time to mind.