Why was the time period between 1865 and 1900 called the gilded age?

It was named the guilded age because everything seemed "golden" or amazing and spectacular, but in reality that was just the outside. Inside there was much corruption and other bad happenings during the era. Btw guilded is like where something has a gold like exterior that makes it seem like gold, but inside it could be something as simple as a rock!! ( took APUS History last year)

Hdah.