Does mercury have dirt or gravel

No because it is mostly made up of rocks, ice, craters,

Mercury is one of the four rocky planets in this solar system, along with Venus, Earth and Mars. It has an extremely thin atmosphere, which has resulted in numerous craters from collisions with meteors and asteroids. Astronomers have learned quite a bit about Mercury from radio telescopes and space missions, but much of this planet still remains a mystery, but no it does not have dirt or gravel

The answer is to reassure the reader about dangers of mad cow disease.