No that's a misconception of what dark matter is. It's weirder than that, it neither emits nor absorbs light, which 'opaque dirt' does.

Per Wikipedia:

For many decades, astronomers assumed that dark matter was made of the same baryons (protons and neutrons) as all other known matter, but in a form that had been overlooked because it was non-luminous. It could not be in the form of a diffuse gas or dust, as that would be apparent when backlit by visible stars, but searches were organized for other astronomical bodies emitting little or no electromagnetic radiation such as massive compact halo objects.

However, evidence eventually accumulated that baryonic dark matter could only account for a small fraction of the missing mass. The study of nucleosynthesis in the Big Bang gives an upper bound on the amount of baryonic matter in the universe,[20] which indicates that the vast majority of dark matter in the universe cannot be baryons, and thus does not form atoms. It also cannot interact with ordinary matter via electromagnetic forces; in particular, dark matter particles do not carry any electric charge.