🪵 Polished Crooked River Limbcast - Large Fossil Cast with Tubes & Shrinkwood

This is an extremely rare, old-stock, polished chunk of Crooked River Limbcast , a fossil agate from Oregon that's become nearly impossible to find—especially in this large collector size . At 18 lbs , this piece is bursting with character: botryoidal tube formations , partial shrinkwood structures , and exposed outer wood grain textures that give it a natural, prehistoric aesthetic.

This cut and proven specimen has a polished face , revealing a pattern that strongly resembles Ochoco Tube Agate —so much so, it nearly fooled us! According to its previous owner, the polish may be a spray-on sealer to preserve the surface—but the visual quality remains stunning. Whether you display it or cut it further, this is a true piece of lapidary history .

📏 Measurements (inches - longest - approx.): 8.9 × 9 × 4.8
🪨 Weight (approx): 18 lbs

📝 Description

Crooked River Limbcast is a highly rare agate that formed inside the cavity of volcanic ash-covered trees near the small towns of Post and Paulina, Oregon . These fossilized limb casts come from the Clarno Formation , dating to the late Eocene to Oligocene Epoch (approximately 38 to 30 million years ago).

The formation process began when hot volcanic ash buried living trees , instantly burning out the wood and leaving behind hollow molds in the shape of the original branches or trunks. Over time, these voids were filled with chalcedony , jasper , or other silica-rich minerals , creating stunning pseudomorphs that often preserve the external texture of wood. Each Crooked River Limbcast is a prehistoric fossil and a collectible lapidary material , prized for its geologic significance and natural beauty .

👉 Crooked River Limbcasts are the same as Congleton Hollow limbcasts , as far as we know—both names refer to the same general deposit area and are often used interchangeably by collectors and dealers.

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📏 Additional Notes

• Natural Stone: This is a cut and proven piece of natural fossil agate , with visible structure and polish. As it is a slab-style slice , it has been cut on at least one side to reveal the internal pattern.

• Photos: All photos are taken with the stone dry, as the face is polished.
  👉 This piece is polished , though the exact type of finish (spray vs lapidary) is uncertain.