Year of Discovery vs. Year Approved

Could someone please explain the general rules regarding the dates shown in the 'Year of Discovery' field?

What exactly is deemed as the 'Year of Discovery'? Are the terms 'discovered' and 'first found' understood as the same?
It looks like pre-1959 the year of discovery is the year of the first mentioning in a publication, which is a standard practice in science, and post-1959 it is still the year of the first publication which now becomes official if done after the IMA approval.
In the IMA age, the logical timeline of events looks like this:
1. new unknown mineral found (=discovered?)
2. submitted to IMA
3. IMA approved
4. published.
If that is correct, then the year of discovery cannot be later than the year of IMA approval. Yet in many cases it is.

Also, what if a mineral was first found and named differently from its later adopted name of the same species (e.g. vanadinite) or becomes redefined (e.g. apatite or monazite)? The discovery year should still remain the same - right? - otherwise it becomes the 'Year of Naming'.

Thanks in advance for your clarifications and comments.

Michael,

Your timeline is absolutely correct. The problem is the year of discovery is not always known and the describers of new species often neglect or for some reason are reluctant to mention the year of discovery, or the discoverer. Many of them do not think it is important and there are no brownie points for such trivia in science. You are quite right that the year of discovery should not be later than the IMA approval, however, in the case of some amphiboles it is possible to have an IMA accepted name without an actual mineral species. It is a kind of preapproval for the name only. When the species is eventually found in nature, it has to go through the regular IMA approval process.
Laszlo