In Colorado, as in most parts of the world, building stone for local use
is quarried locally. Two of the state’s stones, however—Yule Marble from
the Crystal River Canyon, and Lyons Sandstone of the Front Range—have
been more widely used.
The Yule Marble, or Yule Colorado Marble, was produced by metamorphism
of Leadville Limestone in an area intruded by the Treasure Mountain
Granite, thirty-five miles south of Glenwood Springs. This exquisite
marble, which has graced many famous monuments and buildings (among them
the Lincoln Memorial and the Tomb of the Unknown Soldier), is known for
its almost uniform snowy whiteness and regular, fine crystallization.
Although its beauty, massive character, and uniformity made it a
sought-after ornamental stone, quarrying was economically marginal
because of the remoteness of the site. In spite of this, nearly
$7,000,000 worth of the marble was produced before the quarry closed in
1940.
[Illustration: Pure white marble was quarried for many years at the Yule
Colorado Marble Quarry, about three miles southeast of the village of
Marble. (U. S. Geological Survey photo)]
The Lyons area, north of Boulder, provides pink, hard, even-grained
sandstone which splits readily into slabs or flagstones. These are used
in the Denver-Boulder area for sidewalks and patios as well as for
facing buildings. Quarries owned by the University of Colorado provide a
constant supply of handsome facing material and flagstone for new
university buildings, although in recent years the high cost of stone
construction has limited its use on the campus.
[Illustration: Lyons Sandstone is quarried near Lyons, Colorado. The
salmon-colored sandstone splits along surfaces defined by slight
differences in size and arrangement of the sand grains. (John Chronic
photo)]
[Illustration: Most of the buildings of the University of Colorado are
faced with Permian Lyons Sandstone, which is widely used for buildings
and flagstones throughout the Boulder-Denver area. The University
Museum, shown here, was established in 1902, and contains over a million
scientific specimens, including many Colorado fossils and minerals.
Exhibits in the Hall of Earth portray Colorado’s geologic history.
(Tichnor Bros. photo)]
The Lyons Sandstone was deposited as beach and bar sand along the edge
of a sea which lay east of the Front Range in Permian time. After
deposition, the sand was deeply buried and compacted. Now tilted up
along the Front Range uplift, it comes to the surface along the east
side of the range. Only between Fort Collins and Boulder does the stone
have the desirable combination of hardness, thin-beddedness, and color
which makes it desirable for ornamental use. The pink color of the Lyons
Sandstone is derived from iron oxides, mostly hematite, disseminated
between the sand grains. Dendrites (often erroneously called fossil
ferns or plants) ornament some slabs; they were formed by
crystallization of manganese dioxide from groundwater as it slowly
percolated through the rock.