
Rockhounding Colorado
Colorado is an extraordinary state for rockhounding. The state is famous for silver and gold mines. Colorado also has numerous fossils sites, including fabulous dinosaur sites and tracksites as well as petrified wood. In addition, Colorado has an amazing variety of minerals and gemstones, including its famous well crystalized amazonite and smoky quartz specimens. Dozens of meteorites have been found in the state. Colorado also is home to several astonishing state and national parks and monuments.
State Rocks, Gemstones, Minerals, Fossils, & Dinosaurs
Rockhounding Tip: Knowing state rocks, gemstones, minerals, fossils, and dinosaurs often can be very useful information for rockhounders. Ordinarily, states with significant mineral deposits, valuable gemstones, fossils, or unusual or significant rock occurrences will designate an official state mineral, rock/stone, gemstone, fossil, or dinosaur to promote interest in the state’s natural resources, history, tourism, etc. Accordingly, such state symbols often are a valuable clue as to potential worthwhile rockhounding opportunities.

Yule Marble
State Rock: Yule Marble (2004)
Colorado designated yule marble as its official
state rock in 2004. Yule marble is a
type of metamorphosed limestone found only in the Yule Creek Valley in the West
Elk Mountains of Colorado (south of the town of Marble, Colorado). The
marble was created by heat from an igneous intrusion that metamorphosed the
Leadville Limestone along Yule Creek into white, crystalline marble. This white marble is comprised of almost pure calcite grains tightly joined
to give it a luminous quality. Yule marble is famed for its purity and uniform
whiteness. The marble
deposit was reported in the late 1800s in Gunnison County on Yule Creek
although a producing quarry did not begin operations there until 1906.
The outstanding quality of the yule marble made it
the choice for use in the basement of the Colorado Capitol as well as numerous buildings
and monuments in the United States including the exterior of the Lincoln
Memorial and the Tomb of the Unknown Soldier (which used a 56-ton block of Yule
marble).

Aquamarine
State
Gemstone: Aquamarine (1971)
Colorado designated aquamarine as its
official state gemstone in 1971. Aquamarine is the pale blue, and deep blue to
blue-green, variety of the mineral beryl (the deep green variety of beryl is
the gem emerald). Colorado is one of the major producers of aquamarine
in the United States. The mountain peaks
of Mount Antero and White Mountain in Chaffee County, Colorado are among the
finest quality localities known for gem aquamarine. They are also among the highest in elevation,
located at 14,000 feet. The granite rock of these peaks contains pegmatite
bodies that are characterized by large cavities containing the gem quality
aquamarine crystals. The cavities are
found through a vertical area of a mere 500 feet. The crystals in these cavities range in color
from light blue to pale and deep aquamarine green, and in size from very small
to 6 cm in
length.
Aquamarine was first discovered in pegmatite pockets on Mount Antero in
1881.

Rhodochrosite
State
Mineral: Rhodochrosite (2002)
Colorado designated rhodochrosite as its
official state mineral in 2002. Rhodochrosite is a deep red to rose pink manganese carbonate
mineral found in eighteen of Colorado's counties associated with gold, silver,
lead, zinc, and molybdenum ores.
Rhodochrosite's common crystal habit is the rhombohedrum typical of
carbonate minerals. It is also found in
Colorado as massive, dogtooth, disc like, radiating, granular, stalactitic, and
rosette forms. While there was some debate as to whether the
state mineral should be gold or silver or another mined mineral historically
associated with Colorado, it was decided that rhodochrosite is associated
internationally with the state more than any other mineral. The world's largest rhodochrosite crystal,
called the Alma King, is on display at the Denver Museum of Nature and Science.
It was found in the Sweet Home Mine near Alma (Park County), Colorado. Although
rhodochrosite is most commonly pink and opaque, Colorado's translucent red
variety is prized the world over.

Stegosaurus
State Fossil: Stegosaurus stenops (1982)
Colorado designated Stegosaurus as its
official state fossil in 1982. Stegosaurus was about 25 feet long and eight feet high
and was characterized by its plates and spikes.
Although the average Stegosaurus may have weighed 3.5 tons, its brain
was only the size of a walnut. The Stegosaurus lived in the area we now know
as Colorado 150 million years ago during the Mesozoic era in the Jurassic
period.
The first Stegosaurus skeleton was found just
west of Denver in 1877. Over a century
later, a nearly complete, articulated specimen was found near Canon City and is
now on display at the Denver Museum of Nature and Science. Many other specimens were found in the
world-famous Morrison Formation, named for the town of Morrison, Colorado.
Rockhounding Resources

State-specific rockhounding books (including the books listed here as well as other books), regional rockhounding site guides, and other helpful rockhounding resources are identified - by category - in the Books & Gear section of Gator Girl Rocks with a link to the Gator Girl Rocks Amazon Store where you may easily browse selected resources and securely place an order. Your order will benefit Charity Rocks!

Colorado
Geological Survey
One of the better state geological survey
websites.

U.S. Bureau of Land Management – Colorado
The BLM manages 8.4 million acres of federal
public lands in Colorado.

Western Interior Paleontological Society
- Halka Chronic & Felicie Williams, Roadside Geology of Colorado (2002).
- James R. Mitchell, Gem Trails of Colorado (2d ed. 2008).
- William A. & Cora Kappelle, Rockhounding Colorado (2d ed. 2004).
- Stephen M. Voynick, Colorado Rockhounding: A Guide to Minerals, Gemstones, & Fossils (Rev. ed. 1995).
- Richard M. Pearl, Colorado Gem Trails & Mineral Guide (3d ed. 1972).
- Herbert W. Meyer, Fossils of the Florissant, (2003).
- John T. Jenkins & Janice L. Jenkins, Colorado’s Dinosaurs (1993).
- Dougal Dixon, Camarasaurus and Other Dinosaurs of the Garden park Digs in Colorado (2008).
- David Harris, Colorado Caves: Hidden Worlds Beneath the Peaks (2001).
- Mathew L. Morgan, The Handbook of Colorado Meteorites (2000).
- Allan W. Eckert, Earth Treasures Vol. 4A - Southwestern Quadrant (1987; reprint in 2000).
- James Martin Monaco & Jeannette Hathway Monaco, Fee Mining & Rockhounding Adventures in the West (2d ed. 2007).
- Kathy J. Rygle & Stephen F. Pedersen, Southwest Treasure Hunter's Gem & Mineral Guide (4th ed. 2008).
Museums of Interest to Rockhounders

Denver Museum of
Nature & Science
Denver, Colorado
Formerly named the Denver Museum
of Natural History, the museum's collections include fossils, rocks, meteorites,
gemstones, and minerals. The museum's
specimens include a 13 pound gold nugget found in 1887 as well as the 'Alma
King,' a four-inch rhodochrosite crystal.

National Mining Hall of Fame & Museum
National Mining
Hall of Fame & Museum
Leadville, Colorado
Located in the famous 1880's silver
mining boomtown, the National Mining Hall of Fame & Museum is a monument to
the memory of the men and women who pioneered the discovery, development, and
processing of our nation's natural resources.

Colorado School of Mines - Geology Museum
Colorado School of Mines Geology Museum
Golden, Colorado
The Colorado
School of Mines Geology Museum, started in 1874 by Arthur Lake, exhibits
minerals, fossils, gemstones, meteorites, and historic mining artifacts. The museum includes minerals from Colorado as
well as other localities. The meteorite
collection includes over 200 specimens. In
addition, the museum exhibits one of the ‘goodwill moon rocks’ collected during
the Apollo 17 lunar mission.
.

Morrison Natural History Museum
Morrison, Colorado
The Morrison
Natural History Museum, located near the world famous Morrison Formation,
provides a glimpse of the first important dinosaur discoveries in Colorado
including fossils from the first Stegosaurus and Apatosaurus ever
discovered.

Museum of Western Colorado’s Dinosaur Journey Museum
Fruita, Colorado
Dinosaur Journey tells the story of the
history of life in western Colorado and surrounding areas with real fossils,
cast skeletons and robotic reconstructions of dinosaurs. The hands-on, interactive museum includes
paleontology displays and a working laboratory where dinosaur bones are
prepared for display.

Dinosaur Depot Museum
Cañon City, Colorado
The Dinosaur
Depot Museum exhibits dinosaur fossils from the Garden Park Fossil Area, which
has produced world-class Late Jurassic fossils since 1887. The
Garden Park Fossil Area has produced some of best dinosaur fossils found
anywhere, including three articulated skeletons of Stegosaurus stenops. The
first was found in 1886 and is in the National Museum of Natural History in Washington,
DC. The second was found in 1937 and is
in the Denver Museum of Nature and Science.
The third, the world's most complete, was removed from Garden Park in
1992 and the largest jacket weighing over 13,000 pounds was brought to the
Dinosaur Depot Laboratory for preparation. A full-size replica of this stegosaurus is on
display in the Museum. The museum
includes an active laboratory where visitors can view the preparation of
fossils.
University of Colorado Museum of Natural History
University of Colorado – Boulder, Colorado
The museum’s Paleontology Hall features fossils that can be touched, seen, and felt,
including petrified woods, giant fossil clams, and a dinosaur footprint.

Rocky Mountain Dinosaur Research Center
Rocky Mountain Dinosaur Resource Center
Woodland Park, Colorado
The Rocky
Mountain Dinosaur Resource Center exhibits dinosaurs and other
fossils. It also includes a fossil
preparation lab.
Places to Visit - Interesting Sites To See


An excavated dinosaur bone … and me in 2009
Dinosaur National
Monument
Colorado &
Utah
Dinosaur National
Monument protects a large deposit of fossil bones of creatures that lived
nearly 150 million years ago. The rock layer enclosing the fossils is a sandstone
and conglomerate bed of alluvial or river bed origin known as the Morrison
Formation from the Jurassic Period 150 million years ago. The dinosaurs and other ancient animals were
washed into the area and buried presumably during flooding events. The pile of sediments were later buried and
lithified into solid rock. The layers of
rock were later uplifted and tilted to their present angle by the mountain
building forces that formed the Uinta Mountains. This site provides one of the best
snapshots of Jurassic dinosaurs found anywhere in the world.

Florissant Fossil
Beds National Monument
Teller County,
Colorado
Florissant Fossil Beds National
Monument includes one of the richest and most diverse Eocene fossil deposits in
the world. The site includes huge
petrified redwood stumps up to 14 feet wide and thousands of detailed fossils
of insects and plants. Almost
35 million years ago, enormous volcanic eruptions — now designated the Thirty-nine
Mile volcanic area – buried the then-lush valley and petrified the redwood
trees that grew there. A lake formed in
the valley, and the fine-grained sediments became the final resting-place for
thousands of insects and plants. These sediments
compacted into layers of shale and preserved the delicate details of these
organisms as fossils.

Dinosaur Ridge
Morrison, Colorado
Dinosaur Ridge is part of the Morrison-Golden Fossil Areas National
Natural Landmark.

Me at Dinosaur Ridge in 2005
Dinosaur Ridge Trail
Morrison, Colorado
The Dinosaur Ridge Trail is 1.5-mile trail
along Alameda Parkway, between Rooney Road North and County Road 93. West Alameda Parkway traverses the Dakota
Hogback, which has locally been renamed “Dinosaur Ridge” by the USGS. The National Park Service has designated the
area a National Natural Landmark. Along
the Trail, there are over 15 sites, each marked by an interpretive sign. The sites include hundreds of dinosaur
tracks, a quarry of dinosaur bones, interesting geologic features, and scenic
overlooks of Colorado’s Front Range

Dinosaur Tracksite - Dinosaur Ridge
Dinosaur Tracksite
Morrison, Colorado
The Dinosaur Tracksite was uncovered during
the construction of West Alameda Parkway in 1937. Today, after an expansion of the main site in
1994, over 300 early Cretaceous Period
dinosaur tracks have been identified. Of those at least half are periodically
colored using charcoal by Dinosaur Ridge volunteers to help visitors see the
tracks in the sandstone. The
tracks are those of Iguanodon-like plant-eating dinosaurs and
ostrich-sized meat-eating dinosaurs.
These tracks represent only a small part of the extensive track-bearing
beds of the Dakota Group that can be traced from Boulder, Colorado to northern
New Mexico. Because these strata
represent the shoreline sediments of an ancient seaway that was frequently
trampled by dinosaurs, these beds have been called the "Dinosaur
Freeway."

Dinosaur Ridge Bone Quarry
Morrison, Colorado
Arthur Lakes, a professor at the Colorado
School of Mines, discovered the Late Jurassic ‘Dinosaur Ridge Bone Site’ in
1877. It was referred to as Morrison
Quarry Number Five (of the 14 quarries in the area, only four actually produced
dinosaur fossils – Nos. 1, 5, 8, and 10).
The world’s first Stegosaurus was
discovered at Quarry Number Five (several vertebrae, parts of limbs, and pieces of the
famous plates were uncovered and are exhibited at the Morrison Natural History
Museum). The bones exposed today at the interpretive site are
most likely from Stegosaurus and Apatosaurus, which existed about
150 million years ago, and washed into this small braided stream channel
deposit during a flooding event. The
Bone Quarry is one of a few locations where you can see and touch fossilized dinosaur
bones in place.

Picketwire Tracksite
Picketwire Canyonlands
Dinosaur Tracksite
Comanche National Grassland – Southeastern Colorado
This is the largest dinosaur tracksite
in North America. It is located in Picket Wire Canyon on the banks of the Purgatoire
River on federal public lands managed by the US Forest Service in the Comanche
National Grassland in southeast Colorado approximately twenty miles south of La Junta, in Otero County, Colorado. The
tracksite, which occurs in limestone of the Jurassic Morrison Formation, is the
largest documented assemblage of trackways in North America. Over 1,400 prints in 100 separate trackways extend
across a quarter mile expanse of bedrock.
The tracks include both biped and quadruped dinosaurs. About 150 millions years ago, southeastern Colorado was dominated by a vast
freshwater lake. As the dinosaurs
plodded through the mud along the edge of this lake, they left behind vast
trails of footprints. Later, these muddy
flats were buried and turned to stone. The
tracksite is far from paved roads, but accessible by hiking on foot, by
mountain bike, or by horseback. The US
Forest Service also conducts vehicle access tours.

Marsh Quarry - 1888 - at the Garden park Fossil Area
Garden Park Fossil Area
Near Cañon City, Colorado
The Garden Park Fossil Area is located on
federal public lands managed by the Bureau of Land Management. The Garden
Park Fossil Area is one of the most productive and historically important areas
in the western United States for the understanding of Late Jurassic dinosaur
faunas. The Garden Park area is one of the few places in the Western United
States where dinosaur remains occur from bottom to top of the Morrison
Formation. They have been collected from no fewer than 25 quarries in the
Garden Park area, which is the “type locality” of many species of famous
dinosaurs, including species of Allosaurus, Camarasaurus, Diplodocus, and
Stegosaurus. Two roadside stops occur near two of the historic
quarries in the area. The Cleveland Quarry (also known as the Delfs Quarry,
named for Edwin Delfs, who excavated the quarry for the Cleveland Museum of
Natural History between 1954 and 1957 was across Four-mile Creek near the
valley bottom and produced one of the most complete known skeletons of the
primitive long-necked sauropod, Haplocanthosaurus delftsi. The skeleton is the only mounted specimen of
this genus and is on display at the Cleveland Museum of Natural History in
Ohio. The Marsh-Felch Quarry (0.2 mile
north of the Cleveland Quarry) has a quarter mile long hiking trail to an
overlook of the Marsh-Felch Quarry. The Marsh-Felch Quarry is the type locality
for a number of dinosaur species, including Allosaurus, Ceratosaurus,
Diplodocus, Haplocanthosaurus, Labrosaurus, Morosaurus, and Stegosaurus. The bones of 65 individual dinosaurs were
found in this quarry.

Pikes Peak
Pikes Peak
West of Colorado Springs, Colorado
Pikes Peak is
approximately ten miles west of Colorado Springs. It is not a volcano and has never been
one. The granite rock of which the
mountain is made was once hot molten rock located as deep as 20 miles beneath
the earth's surface. The molten rock hardened
and cooled below the earth's surface as much as one billion years ago. Great forces within the earth's crust pushed
the rocks upward through a process called uplifting which created a dome-shaped
mountain covered with a thick layer of soil and softer rock. Erosion and weathering loosened the softer
layers and carried them away. After
hundreds of thousands of years of erosion and weathering, a tall granite
mountain lay exposed like a large piece of stone waiting for the sculptor to
shape it. Anyone seeing this ancient
mountain would not have recognized it as the mountain we know today as Pikes
Peak. It took the movement of huge glaciers that once existed on the peak to
sculpt the mountain. The glaciers lasted
about one million years and that ice age ended around 11,000 years ago. Acting like a giant cookie cutter, the
powerful bodies of ice gouged out the rock and left deep, straight-walled
basins like the Bottomless Pit with its sharp drop of 1700 feet. The flowing “rivers of ice” carved the U-shaped
canyons that lead down Pikes Peak. Other
v-shaped valleys owe their existence to ordinary streams.

Great Sand Dunes National Park
Great Sand Dunes
National Park & Preserve
Mosca, Colorado
The Great Sand Dunes National Park and
Preserve, located in the easternmost parts of Alamosa and Saguache Counties,
Colorado, protects the tallest sand dunes in North America.

Rocky Mountain
National Park
North Central
Colorado
Rocky Mountain National Park, split by
the continental divide, includes 60 mountain peaks over 12,000 feet above sea
level. We visited in 2004.

Mesa Verde National Park
Mesa Verde National Park
Southeastern Colorado
Mesa Verde National park is located in
southeastern Colorado near the ‘four corners.’
Mesa Verde, Spanish for green table, features numerous ruins of villages
and homes built by the Ancestral Puebloan people (Anasazi) who made it their
home for over 700 years, from about A.D. 600 to A.D. 1300.

Garden of the Gods
Colorado Springs,
Colorado
The Garden of the Gods Park is a
Registered National Natural Landmark and public park in Colorado Springs,
Colorado. The outstanding geologic features of the park are the ancient sedimentary
beds of red, blue, purple, and white sandstones, conglomerates, and limestones
that were deposited horizontally, but have now been tilted vertically and
faulted by the immense mountain building forces caused by the uplift of the
Pikes Peak massif. The Park includes an informative Visitor's Center.
We visited in 2005.

Me at the Garden of the Gods in 2005

Dad and me at the Garden of the Gods in 2005

Red Rocks Visitors Center
Red Rocks
West of Denver,
Colorado
Red
Rocks is a geologically formed, open-air amphitheater that is not duplicated
anywhere in the world. The design of the
Amphitheatre consists of two, three hundred-foot monoliths (Ship Rock and
Creation Rock) that provide acoustic perfection for any performance. There is an informative Visitor's Center.
We visited in 2005.

Me and mom at Red Rocks in 2005

Trail near Yule Marble Mine
Yule Marble Quarry
Marble, Colorado
The Yule Marble Quarry Hiking Trail, outside
Marble, Colorado, provides views of large blocks of scrap marble (that
contained fractures or flaws).

Royal Gorge
Royal Gorge
Cañon City, Colorado
The Royal Gorge (sometimes referred to as the
Grand Canyon of the Arkansas River) is a deep, narrow canyon on the Arkansas
River that cuts through the granite of Fremont Peak. The canyon is about 1,250 feet deep.

Petrified Wood Building
Petrified Wood Building
Lamar, Colorado
Lamar's Petrified Wood building started out as
a gas station, built by lumber dealer W.G. Brown in 1933. The building walls and floors are constructed
of large pieces of petrified wood over 175 million years old.

Granada Flagpole
Granada, Colorado
The base of the flagpole includes rocks from
all fifty states.
Rockhounding Sites for Children & Families

The 'Alma King' rhodochrosite specimen
Colorado has extensive rock, mineral, gemstone, and fossils sites. Many individual sites are well known to rockhounders worldwide. In addition, broad areas of Colorado are known for particular specimens – for example, aquamarine at Mt Antero, topaz at the Tarryalls, and quartz crystals and amazonite specimens at Pikes Peak.
Federal Public Lands
BLM-Managed Federal Public Lands
In
Colorado, the BLM manages millions of acres of federal public lands. Subject to federal restrictions, recreational rockhounds are permitted to collect rocks
and gemstones from most federal lands. Some lands are withdrawn or reserved for
certain purposes such as outstanding natural areas, research natural areas,
recreation sites, national historic sites, etc.

Mom and me looking for rocks in a Western Colorado stream in 2004

Mt. Antero, Colorado
Aquamarine & Other Specimens
Mt. Antero, Colorado
Mt Antero
is one of the highest recreational rockhounding sites in the world. At about 14,000 feet above sea level, the
site has a short season. Recreational
rockhounders head here to look for aquamarine crystals as well as smoky quartz, apatite, topaz, microcline,
beryl, and other specimens. The
specimens occur in small cavities and
pegmatites in granite.

Amazonite & Smoky Quartz
Amazonite & Smoky Quartz
Pikes Peak Region, Colorado
The Pikes Peak region is
famous for its well-known and remarkably well-crystalized amazonite (a variety
of microcline feldspar that is usually green or blue) and smoky quartz
specimens that occur in
granite. Amazonite
occurs in granite pegmatites. Crystal
Peak in Teller County, Colorado also is a well-known site for high quality
amazonite specimens.