Petrichor is the evocative scent of rain falling on dry earth. It is intensely earthy, mineralic, damp, and clean, often carrying a subtle ozonic or metallic tang. The primary sensation is one of wet soil, cool stone, and fresh air immediately after a downpour. Its texture is perceived as cool and moist. While the natural phenomenon is fleeting, the fragrance note aims to capture this moment. In perfumery, it typically behaves as a top or heart note, providing an initial burst of damp freshness and grounding earthiness. Its intensity can range from a subtle whisper of dampness to a powerful, almost muddy richness, depending on the concentration of key components like geosmin. Projection is often moderate, aiming to create an atmospheric aura rather than a sharp, defined scent. Longevity can be challenging to achieve naturally, often requiring synthetic enhancement to persist beyond the initial phase.