They were created by humans; therefore, "artificial", or "manufactured". Just because there is no practical way to distinguish them from the ones that appeared naturally doesn't mean they weren't created artificially.

"But this is a purely philosophical difference then!" Yes, it is. Humans still take such silly differences into an account, consider e.g. replicas of artwork made by the original artist themself. Are they genuine? Debatable!

artificial != manufactured

Artificial: made by people, often as a copy of something natural.

To manufacture: to produce goods in large numbers, usually in a factory using machines.

Seems pretty synonymous to me. Heck, Collins dictionary [0] straight up states they're synonyms.

[0] https://www.collinsdictionary.com/dictionary/english/artific...