A fantasy kids' book that was written as a collection of tales (like a fairytale anthology) about the same kingdom, set in medieval times. There is no set protagonist or plot line, it just all happens to take place in the same kingdom. There were some gems that had powers (there was an opal, a yellow gem, a purple gem, etc.) and there were monsters, specifically dragons and wyverns.
The copy I had was a hardback that was decorated with plastic gems set into the typeface. There were pages of art that were really cool. The title might've been "Tales of the ———" (?).
I read it in sometime between 2013-2018 but I think it was published before 2010?