igneous

Rounded pale-green pebble, likely serpentinite or altered basalt

Probable serpentinite (serpentine-group minerals) or weathered mafic rock; exact identification requires testing

AI-generated identification · may be incorrect

Fine-grained, matte to weakly waxy luster, pale gray-green color, rounded by abrasion; likely Mohs 2.5–5.5 if serpentinite, or 5–6 if basalt. No visible crystals or cleavage are apparent.

Identified August 16, 2026More igneous →

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At a glance

Common name: Rounded pale-green pebble, likely serpentinite or altered basalt
Scientific name: Probable serpentinite (serpentine-group minerals) or weathered mafic rock; exact identification requires testing
Category: igneous
Identified: August 16, 2026
Method: Standard

AI Estimated Value

Typically $0–$5 as a common pebble; up to $10–$30 if confirmed as attractive serpentinite or a collectible locality specimen.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Fine-grained, matte to weakly waxy luster, pale gray-green color, rounded by abrasion; likely Mohs 2.5–5.5 if serpentinite, or 5–6 if basalt. No visible crystals or cleavage are apparent.

Formation & geological history

Likely formed by alteration of ultramafic igneous rock during hydrothermal or oceanic metamorphism, then rounded by stream or beach transport; age is indeterminate from the image.

Uses & applications

As an isolated pebble it has little commercial use; serpentinite may be used decoratively or as dimension stone, while basalt is used for aggregate and construction.

Geological facts

The smooth, subdued green color is consistent with serpentine minerals, but similar appearance can result from weathered basalt, greenstone, or industrial stone.

Field identification & locations

Commonly found in ultramafic belts, ophiolites, volcanic terrains, and gravel or beaches. Check streak, hardness, density, and magnetism; a vinegar test is generally non-diagnostic, while a steel scratch test helps distinguish softer serpentinite from basalt.