Colorado Yule is a marble of metamorphosed limestone found only in the Yule Creek Valley, in the West Elk Mountains of Colorado, 2.8 miles southeast of the town of Marble, Colorado. First discovered in 1873, it is quarried today inside a mountain at 9,300 feet above sea level, in contrast to most marble, which is quarried from an open pit and at much lower elevations.

The localized geology created a marble that is 99.5% pure calcite, with a grain structure that gives a smooth texture, a homogeneous look, and a luminous surface. It is these qualities for which it was selected to clad the exterior of the Lincoln Memorial and a variety of buildings throughout the country, in spite of being more expensive than other marbles. The size of the deposits enables large blocks to be quarried, which is why the marble for the Tomb of the Unknowns, with its 56-long-ton die block, was quarried from Yule Marble.

The forces that created Yule Marble make it distinct from all other American marbles. It was formed by contact metamorphism, unlike Vermont marble and Georgia marble, which are the result of regional metamorphism, a process more associated with the orogeny and erosion of mountain ranges on a regional scale. Tennessee marble did not undergo metamorphism, so is not true marble, which is metamorphic.

Source: Wikipedia. For more detailed information about Colorado Yule Marble visit the Wikipedia Yule Marble page.