W040 / Oregon

Ochoco thundereggs — regional guide

Regional structure group; silica-filled volcanic nodules

An Ochoco thunderegg label starts a comparison—it does not identify the exact bed.

← Western Lapidary Materials
Reference photograph pending

What it is

Regional structure group; silica-filled volcanic nodules

What to look for

Compare volcanic outer material, cavity shape and internal filling. A round rock alone is not a thunderegg diagnosis.

At the cutting bench

Cutting orientation, cavities and fractures matter more than the regional name. Retain a labelled half before turning the whole egg into slabs.

Under the loupe

White Fir, Whistler and other bed labels should remain separate. Do not turn a regional resemblance into a bed attribution.

Source & collecting access

Agency recreation information establishes regional rockhounding context. It does not guarantee any particular site is open today.

Status checked 2026-10-03

The market notebook

No verified realized-price range was established for this entry. Asking prices and sold labels are not interchangeable.

Market researched 2026-10-03

Open the field notes

Formation & evidence

Oregon geological sources document thundereggs in volcanic host rocks. Individual beds may differ in filling, matrix and pattern.

Collecting & trade context

This guide adds the wider central-Oregon context around the named Richardson/Priday records already in the cabinet.

Reading an old label

Preserve the exact name, dates, wrapping and associated pieces. Old-stock age alone does not authenticate a locality or imply exceptional value.

Color comparison limits

Color tags are intentionally unassigned for this regional umbrella; consult individual material records.

What we know—and what we don’t

Visual resemblance can narrow a comparison. Material identity, locality attribution and documented provenance need separate evidence.

C&C Reference Collection

Authenticated reference photography is still being assembled.

Sources & Further Reading
  1. DOGAMI: Fossils, Minerals & Gems

    State geological overview; historical/locality context is not current collecting permission.

  2. Ochoco Rockhounding — Recreation.gov

    Agency recreation listing; verify restrictions and closures separately.

Historic locality information is not current collecting permission. For cutting, use suitable dust controls and material-specific safety guidance.