The Colorado State Capitol was constructed in the 1890s and opened in November 1894. It is located at 200 E. Colfax Ave. and is home of the Colorado General Assembly, and the offices of the Governor, Lieutenant Governor and Treasurer. Designed by architect Elijah E. Myers, the building is intentionally reminiscent of the United States Capitol, constructed of Colorado white granite and topped with its distinctive gold dome. The dome itself is covered in copper panels that are gilded with gold leaf from a Colorado mine. The gold was first added in 1908 to commemorate the Colorado Gold Rush.
The inside of the building is adorned with what is believed to be the entire known supply of Colorado Rose Onyx, a rare rose marble from a quarry near Beulah, Colorado. White Yule Marble from the quarries near Marble, Colorado, was also used throughout the building for the floors.
https://www.colorado.gov/pacific/capitol