She brushed an invisible speck of dust off her shoulder.

It was an almost invisible speck in the distance.

He flicked an invisible speck of something from his coat sleeve.

She removed an invisible speck of something from the sleeve of her sweater.

Which meant that they were so small as to be invisible specks.

She was a nearly invisible speck to his right rear, wiry and quick.

Beck flicked an invisible speck from the sleeve of his tunic.

Annis, bent to pick an invisible speck off her slacks.

Searching for a black speck, invisible within the gold.

The other rocketship was a speck, a mote, invisible because of its size and distance.