In The Wonderful Wizard of Oz, why does the writer uses the colour green to describe the Emerald City?

I am not entirely sure how I should approach answering
this question. The Emerald City in this childhood classis is described with the colour
green because the emerald is a precious stone whose colour is a shade of green that is
notable for its brightness. Often it can have a slightly bluish tinge, however the
overwhelming impression is that of green. So, just imagine you were going to visit a
city that is entirely made out of emerald. What would strike you most of all is the
cumulative colour green in everything. Thus the Emerald City is green and green is used
so much to describe it because the emerald itself, as a precious stone, is green, and
famous for its translucent nature. We can obviously only imagine what it would have been
like to approach the Emerald City, but we can guess it would have been pretty amazing
for Dorothy and friends, and very dazzling.