Geosmin

Say itjee-OZ-min

Petrichor: wet soil after rain, beetroot, muddy and mineral-earthy.

What it is: A molecule made in a lab.
Where it comes from: perfumery grade is synthesised
When you smell it: Dry-down: hours later.
What perfumers do with it: Trace-only accent giving rain-on-earth realism to vetiver, patchouli and green-earthy accords.
Worth knowing: Human noses detect it at about five parts per trillion, a sensitivity that may have evolved to help find water.
Also called: trans-1,10-dimethyl-trans-9-decalol; 'earth smell' molecule

Not on the label of any of the 232 perfumes read so far.

Sources