Wet stone, green from the park. The hour before it gets hot.
Petrichor is not an oil — it's an effect. Vetiver, patchouli, and frankincense make it together; none alone gets close. Cypress at five adds the wet bark after rain. Rosemary at four is the green from the park — herbal, not culinary. The bergamot and petitgrain are the sun on wet leaves.
Fifth Avenue early on a summer morning, walking north — tarmac on one side, the park on the other, still cool and still damp, the city not yet awake enough to smell like a city. There's dew on everything. It's named for the fountain at the top of the park, the one with the figure looking out over the trees.