Calibre e-book viewer: bookmarks

[rd2016]

Using the e-book viewer on my regular computer, I have been bookmarking passages in a particular ebook. I (mistakenly) assumed that bookmarking is akin to highlighting passages on my Kindle. After all this work, I don't know how to find the bookmarked passages--where they begin and end.

But worse, when I go to the bookmarks, I get the general area where the bookmark was made, but not even a precise indicator of where the bookmark starts. Which means I would have to spend the same number of hours determining the passages I originally highlighted to copy and paste them elsewhere.

Furthermore, I have no explanation of what exporting bookmarks is supposed to do. The exporting option assigns the extension "pickle". I find no explanation in the rather useless Calibre manual as to what this means and how it is to be used.

I believe I am viewing the book in MOBI format.

Is there some way out of this pickle?