For some reason, my answer a few minutes ago was missing the subject line. In order to avoid confusion, I am re-sending it with the subject header. Sorry for this.

Am Fr., 3. Apr. 2020 um 09:50 Uhr schrieb Rasser, Michael W. <michael.rasser@smns-bw.de>:
Dear Laura, below are my comments on this:

1)      How are Earth Science Collections curated and organized?  I said
mainly defined by taxonomy, geographical origin, Storage and
Stratigraphic age (based on the Synthesys classifications) Are there any
more?

I agree with Jiri that this is enough!

Just to give a comparison with Andreas' list, our collections are organised and curated not only by systematic, but they cover all of the keywords above:
Level 1:
Amber
Amphibians, Fishes, Reptiles  
Palaeobotany
Paleozoic and Triassic Invertebrates
Jurassic and Cretaceous Invertebrates
Tertiary and Quaternary Invertebates
Quaternary mammals   
Tertiary mammals  
Level 2:
Each collection is then organised by locality, stratigraphy, systematics, or a mixture of them, resp. 

2)      What is the minimum information that would be required in World
collections catalogue for the discoverability of Earth Science
collections and for a research to locate particular collections of
interest.

Not sure, if you mean discoverability of the collection itself, or of the museums objects that are housed in the respective collection. I assume that you mean discoverability of the objects:
  • Taxon name (no higher taxon name needed)
  • Repository number
  • Stratigraphy
  • Geography
  • Housing institution  
  • Curator / contact address
3)      What descriptive information should be considered mandatory or
desirable for each Collection?
  • Name and address of institution
  • Responsible curator / contact person
  • Stratigraphic focus
  • Systematic focus
  • Geographic focus
All the best and stay healthy!
Michael