The cupric asteroids aren't from Crushing Industries, they are a standalone mod (also by Saf).
I've used the "big metallic asteroid" icon from Factorio's Space Age expansion in my icons to replace them actually. You can see it in the gallery images.
The Cupric Asteroids mod itselfs uses only vanilla resources, and has an MIT license (which lets anyone modify and use parts of it freely).
Nevertheless, no content from that mod has been used, so I don't see why it would even be a talking point...?
EDIT: oh, speaking of which, SafTheLamb did not make the "crushed holmium" sprites in crushing industries, right? They're from raiguard's Krastorio 2 assets, guess I should fix my attributions accordingly.