Black Spring Obsidian Field
Utah
obsidiansnowflake obsidianmahogany obsidian
Public land, rules apply · Free
Black Spring Obsidian Field
A rhyolite flow in the Black Rock Desert chilled fast enough to freeze into glass, and the pieces now litter the ground around Black Spring at roughly half an inch to six inches across. Most is jet black, but the Utah Geological Survey notes colored varieties running brown to red, plus snowflake obsidian speckled white and gray. Neighboring parcels include state trust land and private ground, including the old Cudahy mine, so respect marked claim boundaries, watch for cattle and rattlesnakes, and carry out your trash.
The card catalog
| What you can find | obsidian, snowflake obsidian, mahogany obsidian |
|---|---|
| Access | Public land, rules apply — Free |
| Fees | Free; BLM public land published by the Utah Geological Survey as an open collecting site. Personal, non-commercial use only, and do not collect on marked claims. |
| Season & hours | Year-round on a dry road. From the west edge of Delta, 4.3 miles west on US 6/50 to State Highway 257, then about 43 miles south to a BLM sign reading 'Kanosh 26,' then roughly 6 miles east on dirt. UGS suggests four-wheel drive but does not require it. No water, no shade, no services. |
| Kids | Family-friendly — You walk in almost any direction and find obsidian on the surface, which means near-guaranteed success for small children. Volcanic glass takes an edge like a scalpel, so gloves are not optional and bare hands should stay out of buckets. |
| Official source | Utah Geological Survey, The Rockhounder |
| Last checked | Checked against its source August 16, 2026 |
Hours, fees, and access rules change. Verify with the operator or land agency before you go.
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Before you go
What does Black Spring Obsidian Field cost?
Free; BLM public land published by the Utah Geological Survey as an open collecting site. Personal, non-commercial use only, and do not collect on marked claims. Hours, fees, and access rules change. Verify with the operator or land agency before you go.
When is Black Spring Obsidian Field open?
Year-round on a dry road. From the west edge of Delta, 4.3 miles west on US 6/50 to State Highway 257, then about 43 miles south to a BLM sign reading 'Kanosh 26,' then roughly 6 miles east on dirt. UGS suggests four-wheel drive but does not require it. No water, no shade, no services. Hours, fees, and access rules change. Verify with the operator or land agency before you go.
Is Black Spring Obsidian Field good for kids?
Yes — Black Spring Obsidian Field works for families. You walk in almost any direction and find obsidian on the surface, which means near-guaranteed success for small children. Volcanic glass takes an edge like a scalpel, so gloves are not optional and bare hands should stay out of buckets.