Where might this exist? Venus. The same planet that has such extreme temperatures and pressure that it changes carbon dioxide into a state that lies somewhere between gas and liquid. It becomes super-critical. It makes the atmosphere thick like soup as the surface temperatures vaporize metal.
However, about 1.8 miles up into the atmosphere, pressure conditions change. The vaporized metal and minerals begin condensing like rain would. Speaking of rain, while there is little water in and around Venus, it does exist – it also condenses with the vaporized materials.
Then.. it falls like snow. Metallic and grey snow. It collects on mountain tops and reflects sunlight. Even though the atmosphere blocks a lot of the planet’s surface, Venus has a lot of highlands and mountains. Even one (Maxwell) that would make Mount Everest blush (Maxwell is about 7 miles high, almost 40% higher than Everest). So, there is no shortage of real estate on Venus for the snow to land on.
Another interesting note.. there is rain on Venus. It evaporates high in the atmosphere and ascends back up.