Use the visible characteristics and local bedrock setting to identify minerals, rocks and fossils in Oregon. This is an identification reference, not a collecting authorization.
Rock and mineral identification field table
| Possible find | Appearance | Likely setting | Identification checks |
|---|---|---|---|
| Oregon sunstone | Transparent to translucent feldspar; occasional copper shimmer | South-central Oregon volcanic terrain | Feldspar cleavage; hardness 6–6.5; verify aventurescence |
| Thundereggs | Rounded rhyolitic nodules with agate or quartz interiors | Rhyolite and volcanic ash deposits in central/eastern Oregon | Outer nodule and contrasting silicified internal fill |
| Obsidian | Black, brown, or banded volcanic glass | Central and southern Oregon volcanic districts | Glassy texture; curved conchoidal fracture; razor-sharp edges |
| Agate and jasper | Banded translucent chalcedony or opaque colored silica | Coastal gravels and inland volcanic terrain | Hardness ~7 and waxy luster; agate may show translucency |
| Petrified wood | Silicified wood retaining bark or growth textures | Volcanic and sedimentary deposits | Wood grain and growth-ring features in hard silica |
Five checks before identifying a find
- Note host rock, general location and geologic setting.
- Photograph every side in natural light with a scale.
- Check hardness and fracture only on loose, legally collected pieces.
- Compare crystal habit and grain structure; color alone is unreliable.
- Confirm land ownership, permit conditions and current closures before collecting.
Interactive Oregon rockhounding map
Explore the Oregon interactive state map and detailed location popups. Pins are geographical references, not permission to enter or remove specimens.
Never enter abandoned workings, extract specimens from protected parks, or collect on private land without permission.