Rockhounding at Glass Buttes, Oregon — Obsidian Collecting on BLM Land
ALLOWED
No permit required
Key Conditions
- Surface collection of raw obsidian is allowed in reasonable amounts for personal use (43 CFR 8365.1-5(b)(2)). BLM Oregon/Washington's 2024 Rock Collecting Guide defines a reasonable daily amount as one that fits in a car trunk or partial pickup load and weighs under 250 lbs
- ARPA (16 U.S.C. § 470aa) prohibits collecting any worked obsidian — projectile points, scrapers, or any piece showing human modification. Glass Buttes was quarried for ~10,000 years and worked material is mixed into the surface scatter
- No motorized vehicles off designated roads — BLM Prineville District regulations apply
- No permit required for personal-use surface collection; commercial collection requires a mineral materials permit from BLM Prineville District Office
- No digging or excavation — surface collection only; subsurface work would enter archaeological site territory and is not permitted
ARPA applies here — worked obsidian is a federal crime to collect
Glass Buttes was a major Native American obsidian quarry for at least 10,000 years. The ground is visually covered with knapping debris — obsidian chips and flakes from ancient toolmaking — mixed in with raw natural material. Under the Archaeological Resources Protection Act (ARPA, 16 U.S.C. § 470aa), any piece of obsidian that shows intentional human modification is an archaeological resource. Collecting it without a permit is a federal crime, regardless of how small or incidental the piece looks.
First-offense penalty: up to $20,000 fine and 2 years imprisonment.
If you find what looks like a formed projectile point, blade, or scraper: photograph it, note the GPS location, and leave it in place. Report significant finds to BLM Prineville District Office at (541) 416-6700.
For thousands of years before European contact, obsidian from Glass Buttes moved across the American West in quantities that archaeologists still puzzle over. Pieces have been traced by geochemical signature to sites in California, Nevada, Washington state, and Idaho — a trade network spanning hundreds of miles, sustained because Glass Buttes produced something no other site in the region did: multiple varieties of high-quality volcanic glass in one place.
That history is still visible on the ground. Walk anywhere on the slopes of the two main buttes and you're walking through the remnants of one of the continent's most productive prehistoric quarry sites. The obsidian chips are so dense in places that the soil surface has a different colour than the surrounding desert. Most of what you see is naturally fractured or knapped debris — the detritus of millennia of toolmaking.
Raw volcanic obsidian is what you're here to collect. Pieces without deliberate edge shaping — nodules, chunks, and natural fragments — fall under the BLM's personal-use collecting rules: a reasonable amount, no permit. The four varieties found here (black, mahogany, rainbow, and the rare fire obsidian) make this site unusual even by Oregon's high standards for rockhounding destinations.
Obsidian varieties at Glass Buttes
| Variety | Appearance | Abundance | Where to look |
|---|---|---|---|
| Black obsidian | Solid black, glassy; conchoidal fracture | Very common | Entire site; large nodules on lower slopes and washes |
| Mahogany obsidian | Red-brown banding or streaks from iron oxide | Common | East-facing wash slopes; look for reddish tint in scatter |
| Rainbow obsidian | Iridescent sheen (gold, green, purple) at specific angles to sunlight | Uncommon | Mid-slopes of both buttes; requires direct sunlight to spot |
| Fire obsidian | Intense multicolor iridescence, visible from multiple angles in thin sections | Rare | Upper slopes of East Butte; typically smaller pieces |
| Apache tears | Small rounded nodules, translucent when held to light | Abundant | Gravelly washes throughout; easiest material to collect in quantity |
Identification confirmed from BLM Prineville District collecting resources and Oregon rockhounding field references. Rarity ratings based on typical visitor reports from this site.
Fire obsidian specimens, East Butte upper slopes
Fire obsidian forms when obsidian contains thin layers of magnetite nanoparticles aligned during cooling — the iridescence is structural, not from chemical colouring. Glass Buttes is one of only a handful of sites in the world where fire obsidian occurs in collectable quantities. Most material is found as small pieces (under 3 inches) in surface scatter on the upper East Butte slopes. Under BLM's reasonable-amount rule, taking a few quality pieces is legal; the rarity of the variety makes restraint reasonable.
The iridescence in fire obsidian is only visible in thin sections or on freshly-fractured faces. A piece that looks like plain dark glass on the ground may reveal full colour once you break a fresh face — but don't break pieces in the field to test them unless you intend to take them.
The rainbow and fire pieces are almost impossible to spot in flat midday light — the surface just looks like black rubble. Go early. Between 7 and 9am when the sun is low and coming from the east, the iridescent pieces catch the light and you can see them from several feet away. I found my best rainbow material in the first hour of light and then spent the rest of the morning working the mahogany washes. By 10am the glare was too flat for the iridescent varieties anyway.
— Rachel Mower, September 2025
BLM personal-use collecting limits at Glass Buttes
Federal regulation (43 CFR 8365.1-5(b)(2)) lets you collect "reasonable amounts" of rocks, mineral specimens and semiprecious gemstones for noncommercial use. It sets no weight. BLM Oregon/Washington's 2024 Rock Collecting Guide, which names Glass Buttes as an area set aside for rock collecting, defines a reasonable daily amount as one that:
- fits in the trunk of a car, or
- is a partial pickup load, or
- weighs less than 250 lbs,
- and is for non-commercial use.
No permit, fee or registration is needed for that. A full pickup load, more than one trip, more than 250 lbs, power equipment or any commercial use needs a BLM permit. The widely quoted "25 lbs a day" is the federal limit for petrified wood (43 CFR 3622.4), not for obsidian.
Material collected for sale, whether at a gem show, online or to a dealer, is outside personal-use rules and needs a permit regardless of quantity. Confirm current rules with the BLM field office before you go.
Getting to Glass Buttes
Conditions verified September 2025. Check road status with BLM Prineville District Office before driving out: (541) 416-6700.
When to visit
Summer (Jun–Aug)
GoodReliable road access. Heat is significant — 90°F+ on exposed slopes by midday at 5,100 ft, with afternoon thunderstorms common in July and August. Start before 8am, plan to leave the buttes by noon. Early morning light (7–9am) is also the best condition for spotting rainbow and fire obsidian.
Fall (Sep–Oct)
GoodBest overall window. Cooler temperatures, lower thunderstorm risk, and the low autumn sun makes iridescent variety identification easier throughout the day. Road typically solid through October. Snow possible from late October.
Spring (Mar–May)
PoorRoad access unreliable — snowmelt can leave Glass Buttes Road soft and rutted well into May. Call BLM Prineville District Office to confirm current conditions before making the drive. At elevation, snow can persist longer than surrounding desert terrain suggests.
Winter (Nov–Feb)
ClosedRoad typically snowbound or impassable. High desert elevation means conditions at Glass Buttes are significantly harsher than at the US-20 highway level. Do not attempt without confirmed current conditions.
Pre-trip checklist — Glass Buttes
- Call BLM Prineville District Office to confirm road conditions if visiting outside June–October: (541) 416-6700
- Bring at least 2 litres of water per person — no sources on-site or within 60 miles
- Wear leather or cut-resistant gloves before handling any material — obsidian edges cut without warning
- Closed-toe shoes with thick soles — not optional at a site covered in sharp scatter
- Know the ARPA rule: worked obsidian (any piece showing deliberate edge modification) cannot be collected
- Bring padded cloth bags or wrapped containers — loose obsidian in a pack will damage specimens and cut through fabric
- Plan to arrive early — best light for iridescent varieties is 7–9am; summer heat makes afternoon collecting difficult
Who Sets the Rules Here
Bureau of Land Management, Prineville District Office
All surface mineral collection on BLM-administered land including Glass Buttes; 43 CFR 8365.1-5(b) allows reasonable amounts of rocks and minerals for noncommercial use, as defined in BLM Oregon/Washington's 2024 Rock Collecting Guide
- FederalArchaeological Resources Protection Act (ARPA) — 16 U.S.C. § 470aa
All archaeological resources on federal land including Glass Buttes; prohibits collection, excavation, removal, or damage to any archaeological resource without a permit
Permits & Licenses
| Permit | Required? | Notes |
|---|---|---|
| Personal-use obsidian collection | No | No permit required for a reasonable daily amount for personal use. BLM Oregon/Washington defines that as fitting in a car trunk or partial pickup load and weighing under 250 lbs. No registration, no fee, no advance notice to BLM. |
| Commercial mineral materials permit | No | Required if collecting for sale or in quantities exceeding personal use. Apply to BLM Prineville District Office, 3050 NE Third Street, Prineville, OR 97754, (541) 416-6700. |
Time & Seasonal Restrictions
- Reasonable amounts only (43 CFR 8365.1-5(b)(2)). Under BLM Oregon/Washington's guide, a full pickup load, more than one trip, more than 250 lbs, or any power equipment needs a permit
- No worked obsidian — pieces showing intentional flaking, edge modification, or other human shaping are archaeological resources under ARPA. This is not a grey area: penalties are federal felony level.
- Surface collection only. Do not dig, excavate, or disturb subsurface material.
- No motorized vehicles off designated roads. The collecting areas are accessed on foot from parking pullouts.
- Collection for commercial sale or resale requires a BLM mineral materials permit regardless of quantity
Equipment Notes
- Leather or cut-resistant gloves — obsidian edges are surgically sharp; even small surface chips cause deep cuts on contact. This is not optional at a site covered in freshly-fractured material.
- Closed-toe shoes or boots with thick soles — obsidian scatter is ankle-deep in places; sandals or thin-soled shoes are genuinely dangerous here
- Padded cloth bags or wrapped containers for transport — loose obsidian pieces will damage each other and cut through fabric pockets
- Loupe or hand lens (10x) — rainbow and fire obsidian show their iridescence at specific viewing angles; a loupe helps confirm quality in the field
- Polarised sunglasses — the high desert at 5,100 ft is intensely bright; useful for both glare and spotting the flash of rainbow obsidian in surface scatter
- At least 2 litres of water per person — no water sources within 60 miles; heat can be severe in summer and dehydration risk is real at altitude
What People Find Here
- Black obsidian — most abundant; large nodules and surface chunks throughout the site; good quality for knapping or display
- Mahogany obsidian — reddish-brown banding from iron content; concentrated in the wash slopes on the east face; distinctive and collectible
- Rainbow obsidian — iridescent sheen visible when held at specific angles to direct sunlight; less common than black or mahogany; most found in the upper mid-slopes
- Fire obsidian — intense multicolor iridescence (green, purple, red, gold depending on angle and thickness); the rarest variety at the site; found primarily on the upper slopes of East Butte
- Apache tears — small naturally rounded obsidian nodules in gravelly washes; abundant and good for beginner collectors who want to take home a quantity of pieces
Penalties for Violations
← Scroll to see all columns
| Violation | Statute | Penalty |
|---|---|---|
| Collecting archaeological resources (worked obsidian, projectile points, tools, or any humanly modified material) | ARPA, 16 U.S.C. § 470ee | First offense: up to $20,000 fine and 2 years imprisonment. Second offense: up to $100,000 fine and 5 years imprisonment. Civil penalties additional. |
| Collecting more than a reasonable amount, or collecting for sale, without a BLM permit | 43 CFR 8365.1-5(b); penalties under 43 CFR 8360.0-7 | Fine up to $1,000 and/or up to 12 months' imprisonment; collected material subject to confiscation |
| Operating motorized vehicle off designated roads | BLM Prineville District travel management plan; 43 CFR § 8341.1 | Citation; fine up to $1,000 |
Etiquette & Leave No Trace
- Leave the knapping debris in place. The dense scatter of obsidian chips covering the ground is not litter — it is the archaeological record of 10,000 years of toolmaking. Walking around it is not always possible, but do not redistribute or collect it.
- Pack out everything you pack in. No facilities means no bins. BLM land near popular collecting sites gets closed over trash accumulation — Glass Buttes has stayed open partly because regular visitors have kept it clean.
- Don't make new trenches or test pits in search of better material. Surface collection is the legal and ethical mode here.
- If you find what looks like a complete projectile point or formed tool, photograph it in place and leave it. Report significant finds to BLM Prineville District Office at (541) 416-6700.
Nearby Alternatives
← Scroll to see all columns
| Site | Distance | Notes |
|---|---|---|
| Succor Creek State Natural Area | 195 mi | Thunder eggs, jasper, chalcedony — different material entirely; BLM Vale District adjacent; high-clearance access |
More Rockhounding Sites Nearby
Distances are straight-line, not driving distance.All 6 rockhounding sites in Oregon
Frequently Asked Questions
What types of obsidian can I find at Glass Buttes?
Four main varieties: black (most common, large nodules throughout), mahogany (reddish-brown banding from iron oxide, found in the east-face washes), rainbow (iridescent sheen at specific angles to sunlight, mid-slopes), and fire obsidian (intense multicolor iridescence, rare, upper East Butte slopes). Apache tears — small rounded nodules — are abundant in gravelly areas and good for beginner collectors.
How do I tell the difference between collectible obsidian and ARPA-protected worked pieces?
Raw natural obsidian breaks with a conchoidal (curved, shell-like) fracture and has no deliberate edge pattern. Worked obsidian — points, scrapers, bifaces — shows systematic flaking on one or more edges, a recognisable tool shape, or platform preparation from intentional knapping. When in doubt, photograph it and leave it. The ARPA penalty for a first violation is up to $20,000 and two years imprisonment — it is not worth guessing.
Do I need a permit to collect obsidian at Glass Buttes?
No permit for personal use. Federal rules (43 CFR 8365.1-5(b)(2)) allow reasonable amounts of rocks and minerals for noncommercial use. BLM Oregon/Washington's 2024 Rock Collecting Guide defines a reasonable daily amount as one that fits in a car trunk or partial pickup load and weighs under 250 lbs. No registration or fee. A full pickup load, repeat trips, more than 250 lbs or any sale needs a permit.
Is the access road suitable for a regular car?
Generally yes in dry conditions — Glass Buttes Road (County CR-5E) off US-20 is unpaved but passable for 2WD passenger vehicles from June through October in a dry year. High-clearance is recommended if you plan to explore beyond the main pullout areas. The road can be impassable after rain and is typically snowbound November through May. Check current conditions with BLM Prineville District Office before making the drive: (541) 416-6700.
Why does Glass Buttes have stricter ARPA concerns than other BLM obsidian sites?
Most BLM mineral sites weren't continuously quarried for 10,000 years. Glass Buttes was one of the most important obsidian sources in the pre-contact American West — material from here has been identified at archaeological sites in California, Nevada, Washington, and Idaho. The ground is densely covered with knapping debris that is visually indistinguishable from natural obsidian scatter. The archaeological sensitivity is significantly higher than at typical BLM collecting areas.
When is the best time of year to visit?
June through October is the reliable window. July and August bring intense heat and afternoon thunderstorms at this elevation — start early and plan to be off the buttes by early afternoon. The low-angle light of early morning (7–9am) is also the best condition for spotting rainbow and fire obsidian, which only show their iridescence at specific light angles. Avoid spring visits unless you've confirmed road conditions — snowmelt can leave the access road soft and rutted into May.
Related Guides
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Disclaimer
Information is provided for general guidance only. Regulations change frequently. Always verify current rules with the official jurisdiction before relying on this information for legal decisions. Permitted Pursuits is not a substitute for official agency guidance. Report an error.
Sources
- BLM Prineville District Office(accessed 2026-05-07)
- 43 CFR 8365.1-5 — Property and resources (collecting 'reasonable amounts' for noncommercial purposes)(accessed 2026-09-25)
- BLM Oregon/Washington — Rock Collecting Guide (2024)(accessed 2026-09-25)
- 43 CFR 3622.4 — Petrified wood: quantity limits(accessed 2026-09-25)
- 43 CFR 8360.0-7 — Penalties(accessed 2026-09-25)
- Archaeological Resources Protection Act — 16 U.S.C. §§ 470aa–470mm(accessed 2026-05-07)
- USGS — Glass Buttes Obsidian Geochemical Characterisation(accessed 2026-05-07)
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