Raindrops are not special. On Earth or on an exoplanet, every drop is just matter surrendering to gravity while pressure and temperature decide its form and its fall. The same Newtonian pull that gives you a drizzle also yanks molten silicates out of alien skies, once local thermodynamics allow rock to exist as vapor, condense into tiny nuclei and then grow into shards of glass that streak down through dense, hot air.
The more extreme claim is that nothing about this process needs exotic physics. Change atmospheric composition, and condensation chemistry changes with it; shift the temperature–pressure curve, and phase transitions move from water to iron, corundum or silicate vapor. On ultra‑hot gas giants, radiative transfer and hydrostatic equilibrium set layers where metal vapors cool enough to supersaturate, nucleation seeds form, and droplets of liquid iron or titanium oxide coalesce and fall, while upper winds shear them into metallic clouds that can re‑evaporate before reaching any solid surface.
Most unsettling is how familiar the script remains. The microphysics that governs cloud droplet growth on Earth—collision–coalescence, terminal velocity, drag—also governs hypothetical sapphire or ruby rain on carbon‑rich exoplanets, where aluminum and oxygen condense into corundum crystals that accrete into gemstone hail. Swap oceans for magma, swap water vapor for silicate or metal vapor, keep the same equations of gravity and fluid dynamics, and ordinary rain physics quietly writes some of the strangest weather in the galaxy.
