WA Map 220px-Map of USA WA

Rockhounding Washington

Washington is a terrific state for rockhounding.  The state offers a variety of different geologic features including active volcanoes, glaciers (including the largest in the lower 48 states), petrified forests, massive lava flows (one of the largest on the planet), caves, caverns, and the scared landscape and geologic features that resulted from the massive glacial Lake Missoula flooding (indeed, there is a massive, multi-ton glacial erratic next to my playhouse in my backyard).  In Washington, rockhounders can find a variety of interesting rock, mineral, gemstone, and fossil specimens including:  agates, amber, carnelian, chert, coal, common opal, concretions, copper, coprolites, fossils (marine and plant), garnets, geodes, gold, jasper, opalite, petrified wood, quartz, & zeolites.  Washington also is home to numerous ghost towns.

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. 

This is a piece of petrified wood that I found near the coal fields in Western Washington near Centralia.

A piece of petrified wood that I found in Lewis County

State Gem:  Petrified Wood (1975)
Washington designated petrified wood as its official state gemstone in 1975.  Most of the petrified wood in Washington grew during the Miocene Epoch, some 12 to 5 million years ago, when the state was swampy and mild, and played host to vast forests of cypress, oak, elm, and ginkgo trees.  Although much petrified wood is buried in river sediments and is thus found in mudstone or sandstone, the trees in ancient Washington grew next to large volcanoes that spewed tons of ash into the air when they erupted.  This volcanic ash settled and buried the trees in place; sometimes they were even engulfed by lava flows.  Layers of logs were preserved with each new lava flow, and as the layers grew deeper, many of the logs became waterlogged and lay protected in deep water.  Over time, water continued to seep through the lava and permeate the wood with silica.  Eventually, the wood fiber was completely replaced by silica, thus petrifying many logs.  The petrified wood is perfect in form and detail to the original wood.  The major petrified wood-bearing unit in Washington is the Columbia Plateau basalts.  In Washington, petrified wood can be found in both eastern Washington and western Washington, which are very, very different.  The best place to see petrified wood in Washington is the Gingko Petrified Forest State Park in Vantage.


Washington - Fossil - Columbian Mammoth

Columbian mammoth

State Fossil:  Columbian Mammoth (1998)
Washington designated the Columbian Mammoth (Mammuthus columbi) as its official state fossil in 1998.  The Columbian mammoth, inhabited the state during the Pleistocene Epoch, 1.6 million to 10,000 years ago, when great sheets of ice covered much of North America.  The Columbian mammoth was huge, standing thirteen feet tall at the shoulder and weighing as much as ten tons.  Fossils of the Columbian mammoth have been found on the Olympic Peninsula (the western portion of the state) and other parts of the state. There are over 40 documented mammoth discoveries in the state.  The most common mammoth fossils found in Washington are the large molar teeth, which are composed of a series of ridged plates, and are sometimes described as looking like a stack of fig newton cookies.  These teeth helped the mammoth chew grasses and other tough vegetation - this large member of the elephant family may have eaten as much as 700 pounds of vegetation a day.


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!

Geological Survey logo - Washington

Washington Division of Geology & Earth Resources


blm logo

US Bureau of Land Management
The BLM manages a great deal of federal public lands in Washington.  Most of the BLM-managed public lands are located on the eastern side of the state.  The website includes information on BLM's rock collecting rules for Washington & Oregon.


Washington Agate & Mineral Society
This is one of the rockhounding clubs that I have joined.  WAMS is a rockhounding club in Olympia, Washington that has been a rockhounding club since 1937.  Rockhounding clubs are a great resource - maybe the best resource - for children and families who are interested in rockhounding.  Information about the club, including meetings, is located on the club's website.

Compass Mentus
Website for an avid Washington rockhounder and one of my best rockhounding buddies.

Washington State Mineral Council
The Washington State Mineral Council has a few claims that rockhounding club members may access.  In addition, WSMC publishes ‘Wagonmasters Maps’ a rock collecting site guide.

Petrified Wood from Western Washington
This is a great site to learn about petrified wood.  Washington, of course, is a great place to find petrified wood.

web- Fossil Crabs

Fossil Crabs of Washington
This is an excellent website to learn about Washington’s fascinating Oligocene era concretions that can contain fossil crabs, snails, and other marine species.  Some of these sites have ben studied since the late 1800s.  The best known areas occur on the Olympic Peninsula along the Strait of Juan de Fuca and in southwest Washington.


Washington Minerals
Website has a handful of general rockhounding locations and terrific photos of Washington minerals.

Northwest Mineral Prospectors Club
The NWMPC was organized to provide support for a group of people wishing to learn about minerals and prospecting and who love the outdoors.  NWMPC has gold claims at several locations (giving its members the opportunity and the right to prospect for gold and other minerals in a designated area).

Northwest Paleontological Association

  • David D. Alt & Donald W. Hyndman, Roadside Geology of Washington (16th ed. 2005).
  • Lanny Ream, Gems and Minerals of Washington (3d ed., 1994).  Written by a northwest geologist and rock collector, this book discusses over 200 rock localities.  Lanny Ream also has written a book about Idaho's gems and minerals.
  • Bob Jackson, The Rockhound’s Guide to Washington (Volumes 1-4) (1987).  Written by a northwest geologist and rock collector, these books (all of which are out of print) discuss numerous Washington rock collecting sites, with maps.  Although most are out of date, the books provide a good starting point.
  • H.C. Dake, Northwest Gem Trails (3d ed., 1962  - originally published in 1950).
  • Garrett Romaine, Gem Trails of Washington (2007).
  • Allan W. Eckert, Earth Treasures Vol. 3 - Northwestern Quadrant (1986; 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, Northwest Treasure Hunter's Gem & Mineral Guide (4th ed. 2008).

Site - Jerry's Rock Shop

Jerry's Rock & Gem
Kent, WA
This is one of the few remaining long-term rock shops in western Washington.  It's also where mom and dad bought my rock tumbler.



Museums of Interest to Rockhounders

Zoe & Greg - Gingko

Me and dad at the Gingko Petrified Forest in 2005.  This specimen is just outside the museum.  The Columbia River is behind us.

Gingko Petrified Forest State Park
Vantage, Washington
Ginkgo Petrified Forest is a registered National Natural Landmark.  It is regarded as one of the most unusual fossil forests in the world.  The park was set aside as a historic preserve when remains of a fossil forest were unearthed during highway construction in the 1930s.  Petrified wood from many different trees is common in the area, but specimens of petrified Ginkgo are rare.  Most petrified forests are found buried in mud or volcanic ash.  This petrified forest, however, is embedded in basalt.  To explain the fact that the trees were not charred and consumed in the lava flow, the trees likely were downed logs that probably were submerged in the waters of a prehistoric lake or swamp.  The petrified logs are embedded in six to fifteen layers of soil and rock.  Occasional specimens lie on the surface and some specimens occur in ancient peat bogs amid tangles of roots, stumps, and empty tree molds.  Many of the fossils are an opal formation and are clearly and beautifully grained.  This opal formation is quite different from the agate/jasper formations in Arizona.  The Park includes a museum that exhibits stunning specimens of polished petrified wood as well as some other local specimens.


Site - Mt St Helens VC

The visitor center near Castle Rock.

View from the Johnston Ridge Visitor Center.  That's me, grandma, and mom in 2012.

Mount St. Helens Visitors Center
East of Castle Rock, Washington
The Center features walk-through interpretive exhibits and award-winning theater programs to educate the visitor on the tale of events that led to the 1980 volcanic eruption.   The Johnston Ridge Visitor Center, located inside the Mount St. Helens National Volcanic Monument, is much closer to the crater and also is worth visiting.


Museum - Stonerose Fossil florissantia quilchenensis

Stonerose Interpretive Center & Eocene Fossil Site
Republic, Washington
The Stonerose Interpretive Center & Eocene Fossil Site has a collection of Eocene fossils (approximately 50 million years old).  In addition to visiting the interpretive center, rockhounds are allowed to collect fossils (small fee).  Collecting is limited to three fossils and the museum reserves the right to keep unique fossils for the museum collection.


Museum - Burke

Mom took this picture of me and a friend while we were visiting the museum on a school field trip during second grade.

Burke Museum of Natural History & Culture
University of Washington - Seattle, Washington
The Burke's mineralogical collection is one of the finest on the Pacific Coast.  Unfortunately, it is not exhibited.  Rather, the museum has a rather odd permanent exhibit called 'Life & Times of Washington State' that attempts to depict Washington history starting when most of Washington was covered by an ancient sea.  Visitors can walk through Dino Times and see giant skeletons of dinosaurs, including a stegosaurus, an elasmosaur, and a 140-million-year-old allosaurus (never mind that there are no dinosaur fossil localities in any part of Washington).  Among the other specimens on display are beautiful 40 to 35-million-year-old fossil crabs (which, thankfully, actually are found in Washington), a cast of a 10,000-year-old mastodon (again, never mind that the state fossil is a mammoth; not a mastodon), and a 20,000-year-old saber-tooth cat.  There is, of course, the 12,000-year-old giant ground sloth that was found during construction at Sea-Tac Airport (the head, however, is not original as it simply was never found). 


Museum - Yakima Valley Museum

Yakima Valley Museum
Yakima, Washington
The museum includes a Miocene forest exhibit that features 15-million-year-old trees, unearthed from a ridge in the Yakima Valley and reconstructed inside the museum.  In addition, a ‘Time Tunnel’ exhibit provides a glimpse of the Yakima Valley 25 million to 10,000 years ago.


Geology Museum
Washington State University – Pullman, Washington
Washington State University’s School of Earth & Environmental Sciences has rock, mineral, and fossil displays in the Webster Physical Sciences Building.


Museum - WWU Geology

Geology Department
Western Washington University – Bellingham, Washington
Western Washington University’s Environmental Studies Building displays a variety of rocks, minerals, and fossils.  The ground floor has mineral specimens; the second floor corridor is lined with fossils, including giant Pleistocene bears and mammoth trunks, local rocks from the Cascades, displays from Bellingham-area coal mines, and Chuckanut fossils.  In addition, a newer display exhibits the 11-inch foot track of Diatryma, a seven-foot tall flightless bird that roamed the river plains of western Washington in the Eocene (about 50 million years ago).  The track was recovered from debris exposed in the Racehorse Creek landslide in 2009.  The Racehorse Creek site has been a rockhound favorite for generations.


East Benton County Historical Museum
Kennewick, Washington
The museum includes local petrified wood and arrowheads.  The museum, however, is famous for its exhibit pertaining to ‘Kennewick Man’ – the skeletal remains of a prehistoric man found on the banks of the Columbia River in 1996.  Kennewick Man’ is one of the most complete ancient skeletal remains ever found.  Note:  Although the museum has a cast of the skull, the skeletal remains have been the subject to litigation and are not at the museum.

Museum of Culture & Environment
Central Washington University – Ellensburg, Washington
The museum currently has an exhibit regarding the ‘Wenas Creek Mammoth’ that was discovered in 2005 near Selah, Washington.


Washington Department of Natural Resources
Olympia, Washington
The State DNR has a small display of Washington rocks, minerals, and fossils as well as a small mineral resources library.


Gold Museum
Liberty, Washington
The Liberty Fire Hall in the historic Liberty town site also serves as a very small museum (a few panels and storyboards) for Liberty gold.


IMG 1049

That's me in 2012 at the museum

CREHST Museum & Science Center
Richland, Washington
The Columbia River Exhibition of History, Science, & Technology (CREHST) includes a small exhibit of Washington rocks.  In addition, it has a small exhibit regarding local mammoth fossils and the Glacial Lake Missoula floods that shaped eastern Washington.


Me and the meteorite specimen at the Pacific Science Center in 2012

Pacific Science Center
Seattle, Washington
The Pacific Science Center has a very small exhibit of interest to rockhounders.  In addition to a meteorite specimen (from the Campo del Cielo area in Argentina), the Center has a small dinosaur display with a very small exhibit of fossils.


Museum - Tacoma

Washington State History Museum
Tacoma, Washington
The History Museum has a small geologic exhibit and very small display of state rocks, minerals, and gemstones.


Site - maryhill museum

Maryhill Museum of Art
Goldendale, Washington
The Maryhill Museum of Art has a small collection of rocks included within its American Indian exhibits.  Nearby, is Samuel Hill’s replica of Stonehenge.



Places to Visit - Interesting Sites To See

Zoe - Gingko Museum

Me at the Ginkgo Petrified Forest


Visiting the Museum in 2012

Gingko Petrified Forest State Park
Vantage, Washington
Ginkgo Petrified Forest is a registered National Natural Landmark.  It is regarded as one of the most unusual fossil forests in the world.  The park was set aside as a historic preserve when remains of a fossil forest were unearthed during highway construction in the 1930s.  Petrified wood from many different trees is common in the area, but specimens of petrified Ginkgo are rare.  Most petrified forests are found buried in mud or volcanic ash.  This petrified forest, however, is embedded in basalt.  To explain the fact that the trees were not charred and consumed in the lava flow, the trees likely were downed logs that probably were submerged in the waters of a prehistoric lake or swamp.  The petrified logs are embedded in six to fifteen layers of soil and rock.  Occasional specimens lie on the surface and some specimens occur in ancient peat bogs amid tangles of roots, stumps, and empty tree molds.  Many of the fossils are an opal formation and are clearly and beautifully grained.  This opal formation is quite different from the agate/jasper formations in Arizona.  The Park includes a museum that exhibits stunning specimens of polished petrified wood as well as some other local specimens.


Zoe - Mount St Helens Top

Me - at age 6 - on the summit of Mount St. Helens (snow-capped Mt. Adams is behind me to the east).  I'm at the crater rim - the snow on the inside melts later in summer because the rim is on the south side of the volcano.

Me - at age 12 - hiking near the Johnston Ridge Observatory with the volcano in the background

Mount St. Helens National Volcanic Monument
Mount St. Helens
Mount St. Helens erupted in 1980 and devastated approximately 230 square miles of forestland.  There are visitor centers as well as trails and interpretive exhibits pertaining to the eruption.  In addition, climbing permits are available to climb to the summit of the 8,000-foot southern rim of the volcano’s crater.  From there, climbers often can see Mount Rainier, Mount Adams, and Mt. Hood.  I climbed to the summit on 7-7-07.  I was six years old.  It was amazing.



Dry Falls in 2012

Site - Glacial Lake Missoula

Glacial Lake Missoula & the Flood Path

Dry Falls - Glacial Lake Missoula Flood
Grant County, Washington
Dry Falls is believed to be the greatest known waterfall that ever existed.  It is a three and a half mile-long scalloped precipice that is ten times the size of Niagara Falls.  At the end of the last ice age, when the ice dam holding back glacial Lake Missoula broke, catastrophic flooding channeled water at 65 miles per hour through the Upper Grand Coulee and over this 400-foot rock face.  At this time, it is estimated that the flow of the falls was ten times the current of all the rivers in the world combined.
Today, visitors can view the site from the Dry Falls Heritage Area (managed by Washington State Parks).  The Visitors Center includes information about the Dry Falls and Ice Age floods as well as the Miocene lava flows.


Site - mima mounds

Several of the mounds are visible behind me.

Mima Mounds Natural Area Preserve
West of Littlerock - Thurston County, Washington

The site is famous for mounds eight to ten feet high and twenty to thirty feet in diameter spread across miles of meadows.  Once thought to be ancient burial chambers or rodent dens, they now are believed to be the result of Ice Age freeze-thaw patterns or glaciation.



A view of Mount Rainier from the visitors center at Paradise.  That's mom, me, my cousin Ella, and my grandma in 2010.

IMG 1031

The Palisades (basalt columns) south of Mount Rainier.  This is a great place to stop and stretch your legs.  I stopped there in 2012.

Mount Rainier National Park
Pierce & Lewis Counties, Washington
Mount Rainier is an active Cascade Range stratovolcano encased in over 35 square miles of snow and glacial ice.  The 14,410-foot mountain is surrounded by lush old growth forests, spectacular subalpine meadows, and a National Historic Landmark District that showcases the "NPS Rustic" style architecture of the 1920s and 1930s.  The Park includes the lowest elevation glacier (Carbon River Glacier).


Site - Mt Baker

Mt. Baker

North Cascades National Park
North Central Washington
The North Cascades are still rising, shifting and forming.  Geologists believe that these mountains are a collage of terranes, distinct assemblages of rock separated by faults.  Fossil and rock magnetism studies indicate that the North Cascades terranes were formed thousands of miles south in the Pacific Ocean.  Attached to slowly moving plates of oceanic rock, they drifted northward merging together about 90 million years ago.  Colliding with the North American Continent, the drifting rock masses were thrust upwards and faulted laterally into a jumbled array of mountains.  The collision broke or sliced the terranes into north or south trending faults that are still evident today.  Over time, these predecessors to today's North Cascades were further faulted and eroded to a nearly level plain.  During the past 40 million years, heavier oceanic rocks thrust beneath the edge of this region.  Intense heat at great depths caused them to melt.  Some of the melt rose to the surface as fiery volcanic eruptions like Mt. Baker.  The rest recrystallized at various depths to form vast bodies of granitic rock forming the core of the North Cascades.  These gigantic pinnacles have pushed upward to majestic heights again, exposing the roots of the ancient collision zone.  Scientists agree North Cascades geology comprises some of the most complex and least understood geology in North America.


Site - Olympic NP

Olympic National Park
Olympic Peninsula, Washington
The Olympic Mountains were born in the sea.  The basalts and sedimentary rocks that form the mass of these peaks were laid down 57 to 18 million years ago offshore, then uplifted, bent, folded and eroded into the rugged peaks you see today.



My cousin Ella, my grandmother, and me at the Klondike Gold Rush National Historic Park in 2010.

Klondike Gold Rush National Historic Park
Seattle, Washington
Klondike Gold Rush National Historical Park commemorates the Klondike Gold Rush of the late 1890s.  The gold rush, of course, was in the Yukon Territory.  The Historical Park has units in Alaska as well as Seattle, Washington.  The Seattle site includes a museum.


Site - Layser cave

Layser Cave
Gifford Pinchot National Forest – South of Randall, Washington
Layser cave is a significant archeological site discovered in 1982 by Tim Layser, a forest service employee.  Native American Indians used it more then 7,000 years ago.


Site - ape cave

Ape Cave Lava Tube
Mount St. Helens National Volcanic Monument
Ape Cave Geologic Site is part of the Mount St. Helen’s National Volcanic Monument.  Ape Cave is located on the southern flanks of Mount St. Helens.  At almost 2.5 miles long, this is the longest continuous intact lava tube in the lower 48 United States.  Ape Cave formed about 2,000 years ago.  As lava flowed from Mount St. Helens, the surface of the lava cooled and hardened, but hot lava kept flowing underneath.  When the flowing lava drained, it left a tunnel.  By the way, don’t look for any apes in Ape Cave. The cave was named after the St. Helen’s Apes, a youth adventure group.


This is a picture of a tree cast that I took.

This is dad and me inside one of the tree casts.

Lava Cast Forest
South of Mount St. Helens
This site, located near Ape Cave in the Gifford Pinchot National Forest, includes tree casts from a 2,000-year-old basalt flow from Mount St. Helens.  The site is known as the Trail of Two Forests and there is an improved trail and interpretive signs.



Dad, mom, and me inside Gardner Cave in summer 2012.

Gardner Cave
Crawford State Park – North of Metaline, Washington
Gardner Cave is the third longest limestone cavern in Washington.  This tourable cave is filled with stalactites, stalagmites, rimstone pools, and flowstone.  I visited the cave in 2012.


Site - Beacon Rock

Beacon Rock
Columbia River, Washington
Located in the heart of the Columbia River Gorge National Scenic Area, Beacon Rock is the core of an ancient volcano.  The ice-age floods through the Columbia River Gorge eroded the softer material away, leaving this unique geological structure standing by itself on the banks of the Columbia River.  Lewis & Clark passed by Beacon Rock – and measured tides, which, of course, indicated that the Corps of Discovery’s destination was near.  Beacon Rock, which was named by Lewis & Clark in 1805, rises approximately 850 feet.  The mile-long trail to its summit provides outstanding panoramic views of the Columbia River Gorge.  You can probably make the climb.  I climbed it - in the cold and rain – with my grandma.  I was four; she was older.  We made it.



The Blue Lake Rhino Cave is located on the basalt cliff wall behind me (2012).


That's me inside the actual Blue Lake Rhino cave in 2012.  The climb to the cave is very dangerous.


You can see a model of the Blue Lake Rhino cast (and some small bone fragments) at the Dry Falls Visitors Center. I took this picture in 2012.

Washington’s Blue Lake Rhino
East end of Blue Lake in Grant County, Washington
Dad often tells me that many people think they are a lot smarter than the evidence would indicate.  A classic example – and people do this all the time – is when people assume that present conditions (or, for that matter, their favorite point in time) have always been like that.  Here in Washington, for example, we often hear claims about salmon in the rivers for all time and timeless ‘old growth’ forests.  Complete nonsense.  Mental malpractice.  Such mindless claims take far less than 1/10 of one percent of the earth’s history and then assert that such was always true.  Never mind, of course, that as recently as 16,000 years ago (out of over four billion years - that's 4,000,000,000), much of the state was covered under a massive glacier.  And, of course, earlier in western Washington, much of the area was the bottom of an ancient sea (hold your breath!) and much of eastern Washington was inundated with massive lava flows … over millions of years (go fish!).  But, I digress.
At one point in time, Washington was home to exotic creatures such as a rhinoceros.  No kidding.  Washington is home to an unusual fossil mold of a fifteen to fourteen million year old small rhinoceros.  It was discovered in the 1930s.  The rhino, commonly know as the "Blue Lake Rhino," was found in a cavity in the Columbia Basin Basalt.  Actually, only a few bones and a fossil mold were found.  The mold is preserved in pillow basalt overlying a thin sand bed.  The rhino probably lay dead in a small pond when lava flowed into the water and hardened, forming a mold around the body.  Scientists from UC Berkeley made a mold of the rhino (and made off with most of the few bone fossils which now are stored in California), which can be seen at the Burke Museum in Seattle.  Visitors can still see the fossil mold of an upside down rhino in the basalt cave.  It is about 300 feet above the lake, on the east end of Blue Lake approximately 25 miles north of Soap Lake, Washington near Sun Village Resort.  The basalt cliff wall is marked.  Access is dangerous.  Take a flashlight.


Washington State Volcanics

Columbia Basin Basalt Flow
Central Eastern Washington
During late Miocene and early Pliocene, one of the largest basaltic lava floods ever to appear on the earth’s surface engulfed about 63,000 square miles of the Pacific Northwest.  Over a period of perhaps ten to fifteen million years, lava flow after lava flow poured out, eventually accumulating to a thickness of more than 6,000 feet.  In between the lava flows, forests grew.  As the molten rock came to the surface, the earth’s crust gradually sank into the space left by the rising lava.  The subsidence of the crust produced a large, slightly depressed lava plain now known as the Columbia Basin (Plateau). The ancient Columbia River was forced into its present course by the northwesterly advancing lava.  The lava, as it flowed over the area, first filled the stream valleys, forming dams that in turn caused impoundments or lakes.  In these ancient lakebeds are found fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals.


Site - Glacial Lake Missoula

Glacial Lake Missoula & the Flood Path

Mammoth Bathtub Ring
Southeastern Washington
The ice age floods, 15,000 to 12,000 years ago, like modern day floods caused extensive damage and loss of life.  One example is the ‘bathtub ring’ of mammoth fossils.  The ice age floods, it appears, killed numerous Columbian Mammoths and skeletons have been found on eastern Washington hillsides in a classic ‘bath tub ring’ configuration.


Soap Lake in 2012.

Soap Lake
Grant County, Washington
Soap Lake is noted for its mineral rich water.  The lake was formed by the Ice Age floods.  The lake’s mineral rich waters produce a soapy film and create a soapy feel.


Site - Tenino Sandstone Quarry

Historic Sandstone Quarry
Tenino, Washington
In the small town of Tenino, south of Olympia, Washington, visitors can see a large historic sandstone quarry (which now functions as a public pool).  The quarry supplied building stone for many buildings in the Puget Sound area, including the state capitol grounds.  The sandstone was deposited in the Eocene Epoch (about 50 to 40 million years ago) when Washington had a subtropical climate and swampy environment with palm trees, swamp cypresses, and tree-sized ferns.  At that time, the area that would become western Washington was a broad, low-elevation coastal plain that extended eastward into central Washington.  Rivers and streams meandered toward a coastal lowland dotted with seasonal lakes, swamps, and lagoons. As the water spread toward the ocean, it deposited bed upon bed of sand, eventually building up several thousand feet of sandstone.


Site - Snoqualmie Falls

Snoqualmie Falls
Between Fall City and Snoqualmie, Washington
Snoqualmie Falls – which is located near an extinct twenty million year old volcano - is a 268-foot waterfall on the Snoqualmie River.  The Snoqualmie Falls were formed by ice and glacial debris flow over 10,000 years ago.  The water plunges 268 feet over a granite cliff and into a 65-foot deep pool.



Sacajawea State Park
Pasco, Washington
Sacajawea State Park is situated at the confluence of the Snake and Columbia Rivers where Lewis & Clark camped on their historic expedition in 1805.  Today, the Park includes an Interpretive Center that includes a variety of arrowheads and other historic artifacts.

Rockhounding Sites for Children & Families


I visited Stonerose in 2012 and found a rare specimen.  The museum kept one half.

Fossils - Eocene Plants & Insects
Stonerose Interpretive Center & Eocene Fossil Site – Republic, Washington
Commercial (fee access) business.  Visitors to the Stonerose Interpretive Center and Eocene Fossil Site (also known as the Boot Hill Fossil Site) are allowed to collect Eocene (50 million year old) fossils.  Collecting is limited to three fossils and the museum reserves the right to keep unique or extraordinary fossils for the museum collection.  Rockhounders can collect fossils such as plants and insects from a prehistoric lake bottom.  Today, the prior lake sediment occurs as layers of tuffaceous shale.  The shale may be split apart to expose fossils.


The fossil collecting site at Stonerose in Republic, Washington

Specimen Zoe - concretions

That's me in spring 2012 searching for fossil concretions with mom and grandma.

Fossils - Oligocene Crabs
Olympic Peninsula – Clallam County, Washington
Washington has fascinating Oligocene era concretions that can contain fossil crabs, snails, and other marine species.  Some of these sites have ben studied since the late 1800s.  One of the best known areas is located on the Olympic Peninsula along the Strait of Juan de Fuca.  Other well known sites occur in southwest Washington.

Specimen - Concretions Clallam County

Some Oligocene era concretions weathering out of the siltstone.


That's me at Saddle Mountain in 2009 with a piece of petrified wood that I found.

Petrified (Opalized) Wood
Saddle Mountain – Grant County, Washington
Saddle Mountain is located in eastern Washington on federal public lands managed by the Bureau of Land Management.  This renowned collecting site for petrified wood, including opalized wood has been a favorite site for rockhounders for decades.


Specimen - SW Agates with Charlie

Me (center) with two of my rockhounding buddies finiding agates in SW Washington.

Southwest Washington
Southwest Washington has lots of agates.  In addition, there are quite a variety of agates.


Augite Crystals
Doty Hills – Lewis County, Washington
Small augite crystals (phenocrysts) are scattered through a greenish black augite-plagioclase porphyry lithic tuff.  This site has been well known for decades and quite regularly is published.

Site - Denny Creek Garnet Boulder

A boulder (twice the size of a basketball) that I spotted in 2012.  There are visible garnets.  See below.

Grossular Garnets & Quartz Crystals
Denny Creek Canyon – King County, Washington
Grossular garnets occur in vugs and veins in the hard carbonate rock.  The hike to Denny Creek – near the summit of the Cascade Mountains east of Seattle – is spectacular.  The best time to visit is in September when the water levels are low.


Site - Denny Creek Garnets

A close up of some of the garnets in the boulder.

Specimen - Natrolite

Robertson Quarry – Dayton, Washington
Natrolite is a zeolite.  The Robertson Quarry is a trap rock quarry in Eocene submarine pillow basalt of the Crescent formation.  The site is a rock quarry on timberlands owned by Green Diamond Resource Company located 3.5 miles southwest of Dayton, Washington.


Specimen - Opalite

Opalite specimen from my collection.

Diatomaceous Earth Pits – Near George, Washington
The opalite, which is abundant, occurs in the same location as the diatomaceous earth pits that are mined commercially.  The opalite occurs in a variety of colors.


Volcanic Rock
Toutle River, Cowlitz County, Washington
Interstate 5 crosses over the Toutle River at Exit 52.  This river was the major drainage for the Mount St. Helens volcanic eruption in 1980.  Dredged spoils piles of ash still are visible here.  There are good gravel bars at this locality and rockhounds will find interesting volcanic cobbles.


Specimen - Spruce Ridge

Quartz & Pyrite specimen from Spruce Ridge.

Spruce 16 Claim (aka Spruce Ridge)
Middle Fork of the Snoqualmie River, Washington
Commercial (fee access) business [Geology Adventures, Inc.].  The Spruce 16 claim (aka Spruce Ridge) is located in breccia pipes that are part of a mineralized zone in granodiorite of the Snoqualmie batholith.  Copper deposits were first discovered along the Middle Fork of the Snoqualmie River in 1907.
  The Spruce 16 claim pyrite-quartz locality has been known to local rockhounders since the mid-1950s.  It wasn't until 1977, however, that an Ohio-based company began extracting museum-quality mineral specimens from the copper mine with the permission of the owner, the United Cascade Mining Company.  In 1983, Bob Jackson purchased the Spruce 16 claim and has worked the mine since then.  As a result of his work, many major mineral collections contain specimens from the Spruce 16 claim.  See below for information about Geology Adventures, Inc.


Mom and me with some amber specimens (they're small).

Tiger Mountain, King County, Washington
Commercial (fee access) business.  This property is owned by the State of Washington.  Amber collecting is through a permitted field trip with Geology Adventures.


Geology Adventures, Inc.
Commercial (fee-access) business.  Geology Adventures provides geologist-led collecting trips to private mineral and fossil sites in the Pacific Northwest.  The business owns Spruce Ridge and Rock Candy Mine.


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