Full Idea
There is a fundamental distinction between feature-change and generation. ..Materials such as bronze cannot by themselves explain why they are the particular material things they are. But matter which generates things does not endure.
Gist of Idea
In feature-generation the matter (such as bronze) endures, but in generation it doesn't
Source
report of Aristotle (Physics [c.337 BCE]) by Vassilis Politis - Aristotle and the Metaphysics 2.4
Book Reference
Politis,Vasilis: 'Aristotle and the Metaphysics' [Routledge 2004], p.60
A Reaction
This very nice distinction is rather undermined by our modern understanding of generation, but it still might work at a lower level. Transmuting an element by bombarding it is different from reshaping the stuff.