All the planets:

Mercury - Iron Core
Venus - Semi-solid iron-nickel core
Earth - Solid iron-nickle core
Mars - Slid rock core

Jupiter - Rock core
Saturn - Rock and ice core
Uranus - Solid rock core
Neptune - Silicate Rock Core

Pluto - Large Rock Core

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Well ain't that something. I always thought the planets had molten cores. Probably because we've got a molten outer core.