metamorphic

Veined dark-green pebble (likely serpentinite)

Serpentinite, composed mainly of serpentine-group minerals; pale veins may be calcite or quartz

AI-generated identification · may be incorrect

Fine-grained, rounded, dark green-gray with light intersecting veins and a subdued waxy luster. Serpentine minerals are about Mohs 2.5–5.5; hardness and specific gravity vary, so they cannot be reliably determined from the photo.

Identified October 15, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic rock is altered by water-rich fluids, commonly along oceanic crust and tectonic plate boundaries. The specimen’s age and exact formation setting cannot be identified visually.

Uses & applications

Decorative stone and collector pebble; serpentinite is sometimes carved or used as ornamental facing stone. Avoid assuming it is suitable for jewelry without confirming the mineral and vein composition.

Geological facts

The distinctive pale lines are likely mineral-filled fractures, but image alone cannot distinguish calcite from quartz or establish the rock identification with certainty.

Field identification & locations

A smooth, waxy-looking green pebble with irregular pale veins is consistent with serpentinite. Check hardness, streak, and reaction to dilute acid (calcite veins fizz) for a firmer identification; serpentinite occurs worldwide in ultramafic-rock belts.