Emerald
The wonderful green stone of which the Emerald City is built.
First named in The Wonderful Wizard of Oz, ch. 10
walls of which glistened with countless emeralds
What the books say it is
reputation wonderful 1 chapter
I have been to the Emerald City many times, and it is a beautiful and wonderful place; but I have never been permitted to see the Great Oz, nor do I know of any living person who has seen him.”
The Wonderful Wizard of Oz, ch. 10