Glass Butte Obsidian Collection Area

Between mileposts 76 and 77 on U.S. Highway 20, east of Bend on the way to Burns, an unmarked dirt road crosses a cattle guard and runs south off the pavement. The Bend Bulletin warns against the other turn-off, the one with the chicken-wire gate. After a short drive the road begins to gleam. Its surface is speckled with chunks and slivers of obsidian, worn down by decades of cars, and the Bureau of Land Management’s Prineville District, which administers the ground, notes that the natural glass raises the odds of a flat tire. The roads are wide but unmaintained. When wet they turn slick and sticky, rut, and wash out, and the BLM says they may then be impassable. The collection areas lie about two miles in.

From the highway the buttes look like easy-sloping hills. Inside, rocky outcroppings break from their flanks, and the buttes stand about 1,500 feet above the surrounding country. A 2009 BLM handout gives elevations from 4,700 feet near the highway to 6,400 feet at the top of Glass Butte. The cover is scattered juniper, mountain mahogany, sagebrush, grasses and forbs. The same handout lists mule deer, antelope, elk, golden eagles, Canada geese, rabbits and snakes, and cattle graze the butte at certain times of year. August days can pass 100 degrees, evenings turn cold, and snow is possible in any month. Dispersed camping is allowed, but there are no facilities. Every accessible spring is on private land. Hampton, about 12 miles west, is the nearest community, and the BLM calls it very small.

Sheen, lace and pumpkin

“No. We’re hunting for glass,” Mike Whittle told his daughter, the Bulletin writer Makenzie Whittle, from the passenger seat as they drove east on Highway 20 in 2024. They arrived on a 70-degree Saturday and found the ground busy: couples with chisels and knapping tools, families with children hunting the shiny pieces. She wrote that a bucket fills quickly with what lies on the surface and that no digging is needed. Jim Miller, a geologist and flintknapper from Bothell, Washington, wrote for Oregon State University’s Volcano World that fist-sized pieces are abundant. The large pieces of high quality, up to several hundred pounds, take real work with a shovel and pry bar.

The BLM says the area is best known for the range of its colors. The Forest Service lists gold sheen, silver sheen, fire sheen, rainbow, midnight lace, double flow and mahogany. Miller’s list adds red, flame, jet black, pumpkin, brown, green, lizard skin and snowflake. He gives the causes as follows. Tiny crystals of hematite or limonite redden the glass. Gas bubbles stretched nearly flat along the flow layers give the gold and silver sheens. The “snowflakes” are quartz crystals that grew as the glass slowly began to turn to rock. Midnight lace carries contorted streaks, apparently made as layers of stiff magma were stretched and rolled. The BLM’s rockhounding map marks where each kind is found.

The 2009 handout segregates the whole recreation area from mining for obsidian and chalcedony, except for three grandfathered claims in the center. Collectors may take what the BLM calls reasonable amounts, defined there as 250 pounds per person per year, for personal use, using hand tools only. The Bulletin gives the statewide rule for designated sites as 25 pounds a day within that yearly cap. The BLM’s general guide for Oregon and Washington asks collectors to dig no deeper than four feet, fill their holes, leave gates as they found them, and stay out of old mines. The guide also forbids taking arrowheads or flakes from federal land.

A dome of solid glass

Glass Butte is a rhyolitic dome. The BLM dates it to about 4.9 million years ago. The Forest Service says that multiple flows of molten volcanic glass oozed out of the ground here, and that many of the hills are literally solid glass. The Bulletin, citing “Roadside Geology of Oregon,” describes an eruption of rhyolite, tuff and obsidian in which the obsidian “congealed” before it could flow farther, which accounts for the quantity left lying here. Miller notes that obsidian tends to form near the end of a volcanic cycle and often goes with domes like these hills.

Archaeologists Daniel O. Stueber and Craig E. Skinner, writing in 2015, put obsidian over about 746 square kilometers, both as loose pebbles and cobbles on the surface and as veins underground. Some of the underground blocks weigh 45 kilograms or more. Skinner identified nine geochemical varieties of Glass Buttes glass. Some of them turn up in neighboring Crook, Deschutes and Harney counties.

Fourteen thousand years of chipping

Stueber and Skinner call Glass Buttes one of the largest obsidian sources in Oregon. They write that Native American flintknappers have drawn toolstone from it for at least fourteen millennia, and that it lies within the ethnographic range of the Northern Paiute. In 1975, ahead of proposed geothermal leasing, an archaeologist named Mack surveyed 30 square kilometers for the BLM. The survey recorded 131 sites and 15 isolated finds: campsites, large and small knapping stations, hunting blinds, rock walls and quarries. The projectile points ranged from about 13,000 to 900 years before present, and a fluted Clovis point was among them.

In 2011, 41 of Mack’s points were brought back out on loan from the University of Oregon Museum of Natural and Cultural History. Researchers tested them for blood residue and traced the glass to its sources. The Clovis point was made of obsidian from Witham Creek, 120 kilometers away. Other points came from sources such as Cougar Mountain and Buck Spring, and they bore residues of bear, deer, rabbit, bovine and camel. A testing project along Highway 20 in 2006 found one chipping area 800 by 200 meters across, dense with thousands of flakes, its deposits 40 to 60 centimeters deep.

Quicksilver, perlite and Lost Creek

Settlement came to the country west of the butte in a rush. The Prineville historian Steve Lent writes that homesteaders came from across the United States between 1910 and 1913 to the Lost Creek Valley. Many lived in tents with wooden floors and tried dryland wheat and rye. To clear the big sagebrush, wagon teams dragged logs weighted with rocks across it, and the uprooted brush was burned. A trip to Bend or Prineville took about six days, so families made it about twice a year. The settlers asked for a post office named Lost Creek. The postal service already had one by that name, so the office opened on September 13, 1913, in the home of the first postmaster, Charles J. Stauffer, and took his name instead. Drought followed. Settlers killed the coyotes, and the jackrabbits that multiplied ate what crops survived. Most families left within a few years, but the post office held on until June 30, 1940, when the mail moved to Hampton.

Prospectors found mercury-bearing cinnabar at Glass Buttes in 1933. Small operations ran until 1957, and from then through 1970 the Jackson Mountain Mining Company worked on a larger scale, producing 500 flasks of mercury between 1967 and 1970. Stueber and Skinner report that tailing piles still stand east of the buttes and that mercury contamination makes them unsafe to visit. The Oregon Department of Environmental Quality slated them for cleanup in 2001. As of the authors’ writing, no work had been done.

A single private obsidian claim was filed in the mid-1960s, and Stueber and Skinner say several holders have kept the grandfathered claim in force since. Magma Energy explored a geothermal lease of 8,914 acres from 1974 into the early 1980s. ORMAT Nevada explored again in 2010 with a $4.5 million Department of Energy grant, and no plant had been built when the authors wrote. The Supreme Perlite Mining Company staked claims in 1988 and dug four test pits east of the butte, and nothing further was developed.

Knappers on the butte

The old use of the glass never fully stopped. From the 1920s through the 1940s, Ted Orcutt, a Karuk flintknapper, made trip after trip to Glass Buttes. He gathered large pieces of obsidian and roughed out cores there for wealth blades. A companion named Forbes went with him on these quarrying forays, packed the glass out on horses, and wrote about it in 1936. Later came Don Crabtree, whom Stueber and Skinner call the father of American lithic technology studies. He made collecting trips to the buttes, and many scenes of “The Tools of Early Man” were filmed here.

Since 1985 the Glass Buttes Spring Break Knap-in has been held each March, and as many as 100 flintknappers come in a year to break the same glass the Clovis point was struck from.