Nanosand

The … has reported an unanticipated find on the surface of …. Not only are the plentiful sand dunes on the planet composed of rare metal granulate: the sand itself is almost entirely composed of countless broken nanites! These microscopic machines are millions of years old, their structure degraded far beyond any chance for reactivation. While we cannot determine a source of origin for these nanomachines, the society that created them must have been highly technologically advanced. … postulates that the nanites may have been used to terraform the surface …, millions of years ago.

The command below will trigger the "Nanosand" event in Stellaris:

When this event fires, you can choose between these 2 options:

• Astounding.
  • Engineering: +None to None
  • +200 Nanites
• Disconcerting.
  • Engineering: +None to None

Stellaris events fire in chains — one event leads to the next. Here is how Nanosand (distar.280) connects.