Did You Know This is Colorado’s Official State Rock?

Colorado has an official state flag, a state seal, two state songs and many other official emblems and symbols. Included in that list is an official state rock, which has played an important role in Colorado's history.

Colorado's official state rock is yule marble. Following a petition to Legislature from the Lakewood Girl Scout Troop 357, it was designated as the Colorado State Rock by Governor Owens on March 9, 2004.

Yule Marble is a white marble made almost entirely of pure calcite. It's known for having a luminous quality and smooth texture. 

The first discovery of the this shiny, white rock in Colorado was by Geologist Sylvester Richardson along the Yule Creek in 1873. It was then rediscovered in 1874 by George Yule, of whom the rock bears its name. Prospectors continued to take note of the area’s marble deposits throughout the 1880s, but since they were primarily interested in precious metals, miners initially made no attempt to quarry the stone.

The deposits in the Crystal River valley are the only major source of marble in Colorado. These deposits situated at 9,300 feet above sea level are about 50–60 million years old.

From 1884 to 1905 a string of quarries came and went There were a few attempts to produce marble quarries in the mid 1880s, but it wasn't until 1906 that a successful mill operation called the Colorado Yule Marble Company was established.

Demand for marble went up after 1903, when a large fire in New Jersey showed that the material withstood intense heat. The outstanding quality of yule marble made it the choice for use in the basement of the Colorado Capitol, as well as numerous national monuments in the United States, including the Washington Monument, the Lincoln Memorial, and the Tomb of the Unknown Soldier.

A commercial yule marble quarry remains in operation today.