Why did writes mark twain and Charles warner name the late 1800s the gilded age?

Mark Twain and Charles Dudley Warner coined the term "Gilded Age" in their 1873 novel, which satirically depicted the period of rapid economic growth and ostentatious wealth in the late 19th century. They used "gilded" to suggest that beneath the surface of glittering prosperity lay significant social issues, including corruption, inequality, and moral decay. The name highlights the contrast between the era's apparent affluence and the underlying problems that plagued society.