Where to Find Obsidian in California: 3 Mapped Sites
California has 3 documented sites where obsidian have been reported, and the best-known are Gem Hill, Amboy Crater, and Glass Mountain. Every site is mapped below with GPS coordinates and links to a full report of access and what's been found there. 3 of the 3 sites are on public-access land.
Last updated: — data compiled by the Rockhounding.org Research Team · methodology
Obsidian Map: California
All 3 obsidian sites in California. Click a pin for the full site report.
Where Obsidian Are Found in California
Obsidian comes from young rhyolitic lava flows and domes in the volcanic West. Collect only where rules allow — many obsidian localities have archaeological protections.
The richest reported sites in California: Gem Hill, Amboy Crater, Glass Mountain.
Of the 3 sites, 3 are public access. Check each site report for current land status before you go.
All Obsidian Sites in California
- Gem Hill — Public Access
- Amboy Crater — Public Access
- Glass Mountain — Public Access
How to Identify Obsidian
Obsidian is volcanic glass: jet black (sometimes mahogany-streaked or gray-banded), glassy luster, and a perfect conchoidal fracture that produces edges sharper than surgical steel — handle fresh breaks carefully. It feels lighter than an equally sized ordinary stone. Snowflake obsidian carries gray cristobalite spots; Apache tears are rounded obsidian nodules weathered free of their perlite shell.
Not sure what you found? Try our identification guide →Frequently Asked Questions
Where can I find obsidian in California?
California has 3 mapped sites where obsidian have been reported. The best-known are Gem Hill, Amboy Crater, and Glass Mountain. Each listing on the map above includes GPS coordinates, access type, and what has been found there.
How many obsidian sites are mapped in California?
We have 3 documented obsidian sites in California, compiled from community submissions and published locality records and reviewed by the Rockhounding.org Research Team.
Is it legal to collect obsidian in California?
Casual collecting is generally allowed on BLM and National Forest land for personal, non-commercial use — the standard BLM limit is 25 lbs per day plus one specimen. National parks, monuments, and many state parks prohibit collecting, and private land always requires the owner's permission. Check the site report for each location and verify current land status before you dig.
How do I identify obsidian?
Obsidian is volcanic glass: jet black (sometimes mahogany-streaked or gray-banded), glassy luster, and a perfect conchoidal fracture that produces edges sharper than surgical steel — handle fresh breaks carefully. It feels lighter than an equally sized ordinary stone. Snowflake obsidian carries gray cristobalite spots; Apache tears are rounded obsidian nodules weathered free of their perlite shell.
What should I bring to collect obsidian?
The basics: a rock hammer, safety glasses, gloves, a bucket or padded bag for specimens, and a GPS app with the coordinates from this page. Add a spray bottle — wetting a stone makes color and banding far easier to judge in the field.
⚠️ Always verify current regulations, weather conditions, and access requirements before visiting any location. Information provided is based on community submissions and may not be current or accurate.
Obsidian in Nearby States
Data: community submissions — reviewed and approved by the Rockhounding.org Research Team. Always verify current land status, regulations, and access before visiting any site.