Polished Crooked River Limbcast – Large Fossil Cast with Tubes & Shrinkwood

🪵 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.

📏 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.