AI identification & appraisal estimate

Weathered Chert Nodule / Naturally Occurring Rock

Submitted photo of Weathered Chert Nodule / Naturally Occurring Rock
Photo submitted by the user — not generated by AI

User's notes

Appears to be a very large stone spear, knife, or hand axe found in Guthrie OK measuring 9" x 5.5"

These notes were written by the person who submitted this item. Appraiser.AI has not verified them, and the AI's identification and estimate may rely on them.

AI Estimated Value

Not an official valuation

$10.00 - $25.00

AI estimate as of February 18, 2026 · verify with a professional before acting

AI-Generated · Verify before acting

Everything on this page is generated by AI for informational purposes only. AI can make mistakes — the AI may misidentify items or misattribute them (artist, maker, brand, designer, origin, era). This is not an official valuation and should not be used for insurance, sale, tax, estate, legal, or lending purposes — or any decision requiring a certified appraisal. It is not an authoritative claim about any person, brand, or rights holder — do not share or rely on it as a factual statement about a third party. Always consult qualified professionals before making financial decisions.

This analysis also relies on unverified notes provided by the user, which may be incomplete or inaccurate and could affect the result.

Read the full disclaimer

AI Item Analysis

This item is a large, triangular-shaped piece of stone found in Guthrie, Oklahoma, measuring approximately 9 inches by 5.5 inches. The material is likely a native chert, limestone, or sandstone, characterized by a highly weathered, porous, and pitted surface texture. The coloration is an earthy buff, tan, and light brown, consistent with ground mineralization and heavy patination over time. While the overall silhouette vaguely mimics a large biface or hand axe, it lacks the definitive diagnostic features of an intentional man-made artifact. Specifically, there is no evidence of controlled conchoidal fracturing, percussion flaking, or pressure flaking along the margins to create a sharp cutting edge. The edges appear rounded and eroded by natural weathering rather than sharpened by human knapping. The crusty, vesicular surface suggests it is a naturally occurring geofact or a weathered nodule shaped by environmental factors such as water or wind erosion rather than an Paleolithic tool. There are no visible maker's marks or cultural engravings; its value lies primarily in its status as a geological specimen rather than an archeological relic.

AI Appraisal Report

Upon my virtual examination of this triangular lithic specimen from Guthrie, Oklahoma, I have assessed it as a naturally occurring geofact rather than an anthropogenic artifact. While the silhouette approximates the form of a bifacial tool, a close inspection of the photographs reveals a lack of cultural modification. There are no identifiable strike platforms, bulbs of percussion, or systematic flake scars characteristic of flintknapping. The edges exhibit rounded chemical weathering rather than the sharp, controlled fractures found on genuine Paleolithic implements. The vesicular, pitted texture is consistent with a weathered chert or limestone nodule shaped by thousands of years of environmental exposure. The market for geofacts is significantly lower than that for authenticated archaeological relics. While a genuine 9-inch Paleo-Indian hand axe could command thousands of dollars, a 'nature-made' stone of this type is primarily valued as a pedagogical tool or decorative garden element. Comparable sales for unworked, naturally triangular stones in this size range typically fall beneath $25.00. Note that this appraisal is based solely on digital imagery. For a definitive authentication, an in-person microscopic analysis would be required to rule out heavily patinated ancient flaking. I would also recommend a 'lick test' or acid test to confirm the exact mineral composition, as well as a search for subsurface provenance. Without documented stratigraphy or scientific proof of human intervention, this item is valued purely as a geological specimen. The lack of cultural diagnostic features is the primary factor limiting its market value.

Keep exploring

More geological specimen / geofact appraisals

Get your items appraised

Instant AI-powered appraisal estimates from a photo

Browse More Appraisals