I think the comment was poorly worded with “people” and should be “life” which is still an interesting thought.
Distinguishing between things produced by the natural world, and things produced by life seems like the type of communication strategy that would not help a general audience. I mean, I get what you mean, but 'natural' and 'organic' are taken to be synonyms in common usage.
Those are all lifeforms though. And the "sailing" mechanisms have purpose.
The example you are looking for is a lifeless thin slate of ice/rock that gets pushed by a force such as wind or water.