There are a few reasons why you might not be able to edit areas of the Gem page:
You don’t have the level of access that would allow you to make any edits to the page. If this is the case, and you think you should have this capability, we recommend contacting one of the administrators of your Shelf to review your User Role.
Shelf doesn’t allow you to make edits to the meta data that we automatically add to a Gem. This includes: who added the Gem, when it was added to Shelf, how many times it has been viewed, where it was added from, and when it was last updated.