igneous
Likely water-worn gray pebble
Not identifiable to a specific rock from this image; possibly fine-grained basalt or another dark river-worn rock
AI-generated identification · may be incorrectSmall, smooth, rounded gray specimen with a subdued luster; grain, hardness, cleavage, and mineral composition are not discernible at this scale. A hardness or streak test would help narrow it down.
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Physical properties
Small, smooth, rounded gray specimen with a subdued luster; grain, hardness, cleavage, and mineral composition are not discernible at this scale. A hardness or streak test would help narrow it down.
Formation & geological history
The rounded shape suggests abrasion during transport by water or sediment; the original rock type and age cannot be determined visually. Basalt and other common regional rocks may occur near the reported northwest Washington location.
Uses & applications
Likely a natural pebble with little commercial value; suitable as a personal keepsake or landscaping stone.
Geological facts
Water-worn pebbles become rounded as collisions and abrasion remove sharp edges.
Field identification & locations
Inspect a fresh broken surface with magnification, and test hardness and streak before identifying it more specifically. The image does not provide enough detail to confirm basalt or another particular rock.
