W028 / Oregon

Priday Blue Bed thunderegg agate

Agate/chalcedony-filled volcanic thunderegg material

Use the licensed cut thunderegg image as a source-labelled Priday Blue comparison. Compare complete host-and-core structure, not just a cropped pale center.

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Priday Blue Bed thunderegg agate — source-labelled reference specimen
Cut blue/white chalcedony-filled thunderegg with brown host; source-labelled Blue, not South Blue.

James St. John · CC BY 2.0 · No changes

Source-labelled comparison; locality not independently authenticated. Does not authenticate an inherited specimen.

Image source and provenance · License

What it is

Agate/chalcedony-filled volcanic thunderegg material

What to look for

Use the licensed cut thunderegg image as a source-labelled Priday Blue comparison. Compare complete host-and-core structure, not just a cropped pale center.

At the cutting bench

Cut/polished example supports slab and half-egg comparison. Empty pockets, fractures and host/core contrasts affect useful cutting; measure each piece.

Under the loupe

South Blue, Red, Pony Butte and other named beds must remain distinct. UNL historical Blue/Pony equivalence is not a reliable modern bed crosswalk. A thunderegg appearance cannot identify an individual bed.

Source & collecting access

Existing reviewed ranch evidence says public digging permanently closed, with ranch-dug material offered. This does not authorize access or establish that Blue is currently excavated.

Status checked 2026-10-01

The market notebook

No bed-specific realized transaction or comparable current price retained.

Market researched 2026-10-01

Open the field notes

Color comparison tags

Blue, White/Cream/Clear, Brown/Tan

Geology & evidence limits

Photographer assigns John Day Formation and Miocene age; retain as source metadata pending independent bed mapping. Do not apply it automatically to every Richardson bed.

Collecting & trade history

Collector gallery separates Blue from South Blue and Pony Butte. Historic naming and later ranch names overlap imperfectly; preserve original estate label and date rather than normalizing prematurely.

Reading old-stock material

Preserve original labels, receipts, packaging and associated pieces. Old-stock age does not authenticate a locality or justify a rarity premium.

How to read the color tags

Comparison tags, not origin evidence; non-dominant/secondary colors vary by specimen.

Still unresolved

Bed map and reliable historic-modern name crosswalk; Independent stratigraphic confirmation; Multiple independently labelled Blue examples; Bed-specific production/price evidence

What we know—and what we don’t

Visual resemblance is a comparison clue, not proof of material identity, locality or documented provenance. Keep source labels and estate records separate from your visual assessment.

C&C Reference Collection

Reference examples are source-labelled and do not authenticate the locality of an unlabelled specimen.

Sources & Further Reading
  1. University of Nebraska–Lincoln historical agate database

    Historical specimen-label/bibliography evidence; not current access or image permission

  2. Richardson’s Rock Ranch operator site

    Operator evidence, not production audit. Bed labels must remain distinct; closure is not exhaustion.

  3. Richardson’s Rock Prices

    Asking prices, not verified transactions; no quality-controlled market range.

  4. Eibonvale / David Rix Jefferson County specimen gallery

    Collector label evidence; not surveyed bed boundaries or definitive numbered-bed crosswalk. Images copyright, no reuse grant found.

  5. Priday Blue Bed photographed thunderegg / James St. John

    CC BY 2.0; specimen source-labelled Priday Blue. Formation/age are photographer metadata, not independently mapped.

Cut and polish with appropriate wet methods and silica-dust controls. Historic directions and mine names are not current permission to collect.